November 9, 2010 • 38 mins
Not all animals need the same amount of sleep. Some people get by on five hours a day, while other animals (cats, for instance) can easily sleep upward of ten hours a day. So what is sleep, and why don't animals need the same amount? Tune in to find out.
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Episode Transcript
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Speaker 1 (00:04):
Welcome to Stuff to Blow Your Mind from how stuff
Works dot com. Hey, welcome to Stuff to Blow your Mind.
My name is Robert Lamb, and I'm a senior writer
here at how stuff works dot com. And with me
today is Julie Douglas, who is a longtime writer, editor,
pyrotechnician here at how stuff works dot com. Welcome to
(00:27):
the podcast, Julie, Thanks Robert, I'm really excited to be here. Yeah,
we're gonna be uh taking the podcast often an entirely
different trajectory now. You know, previously we were stuff in
the science lab. Now we're stuff to blow your mind.
It's kind of like a a joy division to new order,
Um Jefferson Airplane to Jefferson Starship kind of shift here.
(00:47):
It's you know, the old version was great, but the
new version is going to be even more amazing. That's right.
I mean we have everything from like our cat's shape
shifters to why are we existing here in this world?
In this universe? I mean, we're just gonna open the
portal and we're gonna start the new iteration. Yes, all right,
let's get this started. Yeah, let's do it. As it happens,
(01:10):
we are both cat owners so we are very familiar
with the site of a cat in its various stages
of sleep, which it seems like they have many, just
based on their their bodily position, right, It's true, they're elaborate. Sometimes.
I really love watching my cat in slumber, and I
look at him sometimes and think, oh my god, why
(01:30):
can't I be you? It just seems so like the
master of the universe here in your sixteen hours of
various positions of sleep. Yeah, we refer to them to
our cats sleep levels based on what kind of bread
product she resembles. So there's like bread mode where she
looks kind of like a loaf of bread, and then
of course when she gets really relaxed, she goes into
(01:50):
full on bagel mode, where she's like, you know, very circular,
kind of looks like a cinnamon bun. Wow. So, and
and they do sleep a lot. In fact, let's see,
what's the uh be terrible for cats? It's like fifty
point six percent of the day give or take leopards
of like twelve point one hours. Yeah, yeah, And I
would definitely say my cats more like maybe on the
(02:11):
sixteen hour. And he's seriously just doesn't do a whole lot.
And I don't know if that's because he's a main
con and he's like this twenty six pound um cat.
That's you know, like I said, the master of the universe. Um,
he can do whatever he wants. So if he wants
to sleep for sixteen hours, it's going to happen. It's
it's it's interesting because obviously most humans with you know,
(02:32):
jobs and and you know responsibilities, don't sleep twelve hours
a day. Um. Yeah, so it's more like in the
six to eight range. And you see a wide variety
of sleep patterns throughout the animal kingdom. So so yeah,
that's that's what we're gonna be chatting about today. Um,
you know, do all animals sleep? And what does that
consist of for different members of the animal kingdom? Yeah?
(02:54):
And why do our cats sleep so much? Yeah? That's
you know, I think that is actually a universal question
that has got to be as words. So we're going
to try to do that by first approaching sleep. Yeah,
what is sleep? Sleep? I think that obviously it's really important.
It is profoundly important on our existence and how we
operate physically, mentally, emotionally. Um, and I think that we
(03:18):
take it for granted but and we think, Okay, we
just close our eyes and we wake up and we
get going. Um. In fact, there's so much more going on,
and I think that we kind of need to revisit
the basics really quickly just to get an idea of
how complex sleep is. So you so let's just do
a quick recap. I'm sure we've all heard this in
school at one point or another, but you know that
(03:38):
there's stage one, which is the lightest sleep, and that's
when we kind of start to relax our muscles a
little bit. And is this the point where you're you're
reading your book at night and you suddenly start reading
words that aren't actually in the book. Yeah, they all
start to sort of melt together. And this is also
the point to where you feel like, well, they're like,
(03:59):
oh gosh, feels so great. You know that little voice
in your head I think, so I fallen asleep, that's awesome.
And then all of a sudden, you feel like you're
tripping or falling. Um, And that's really your muscles sort
of working themselves out. So that's stage one, and stage
two is when your breathing patterns and your heart rates
start to slow down a little bit. And your body
temperature takes a little bit of a dip. And then
(04:21):
stage three or when the delta waves start to roll
in and lull you into a deeper sleep, although you're
still sort of fighting with that lighter sleep. And then
stage four is known as the delta sleep, which, um,
it sounds like you should really say the adult asleep
because it you know, it's that really slow wave. Um.
(04:41):
And that's when you're getting thirty minutes of truly deep sleep.
And that is also when you're capable of sleep walking.
So yeah, So I don't know if you ever sleepwalked
when you were a little No, I don't think I did.
Know I did a lot, and so my parents would
see me cruising through the house like three am, and
my hands would be up like Frankenstein. So I literally
(05:03):
thought I was Frankenstein. I was rolling around the house
like that. But wait, in the dreams or just as
a child, you were convinced you were Frankenstein in the dream.
In the dream, yeah, I mean, because kids are weird,
I could you know, that's kind of awesome. I kind
of wish that I had been a kid who thought
that she was Frankenstein because I could really freak out
the neighbors and just dream fire. Um. That sounded like
(05:26):
Robert de Niro's Frankenstein. Sorry about that. Um. And then
stage five is when remickers. So that's when you're dreaming, um.
And that's when you're really working things out, all that
data that you've processed throughout the day. Um. And that's
also where you might be having a dream that's say
a dog is mauling your face, god forbid, and a
(05:47):
dog might be having a dream where it's mauling a
humans face exactly. Yes, yeah, and total totally parallel dreams
at the same time. And the cool thing about this
is that, uh, you have a sort of built in mechanism,
paralysis mechanism to make sure that you don't freak out
during that time period, so that dog doesn't leap out
and try to bite in its dream and I don't
(06:09):
try to you know, take the dog off of me
and smash it or interesting. So like that. So many
of these episodes you hear about where like somebody's having
a dream and they start like strangling their spouse or
something like you know, um, like that's not in this
stage then no, No, I think there's something else going on. Well, yeah,
because I think I'm probably thinking of Ozzy Osborne. So well,
(06:30):
you have to wonder too if there are certain medications
or substances that might be messing with the natural rhythms. Yeah,
I mean, I don't know that Azzy was ever on anything,
but no, no, yeah, I mean that's that's pretty far
fetched for him. But yes, so you never know. That's, um,
there's certainly external forces that could be acting on that. Okay.
(06:50):
So there, So we're in this stage, we're dreaming the
brains being cleared up, and we're going through these stages
about ninety minutes every ninety minutes, so there's a ton
of stuff that's going on, and we're also kind of
flailing around, moving around. I think I've read a stat
somewhere that we move around at least seven times per hour.
So it's not the it's not just the slumber that
(07:11):
we think of. That's all peaceful and you know, the
cats called up by your head. I need that staff
next time I'm kicked out of bed at three in
the morning from moving too much. Yeah, yeah, see that
that would be helpful maybe maybe, Yeah, I mean probably
can't like actually present the stats at three in the morning,
be like, whoa wait, slow down, check out this review,
this the study, and the Scientific American. I'm totally supposed
(07:33):
to move around. You should be concerned if I'm not
kicking you in my sleep, you know. Yeah, on second FID,
that might exacerbating the situation. UM. So it's good to
have an understanding of just what basically what sleep is,
because that's the model that we use UM to study
other animals, other creatures. We know about theta waves delta waves,
so you know that when they go into these slow
(07:54):
low wave states, that there that their brains are preoccupy
hid and that they're dreaming or sleeping, and that's what
we assume at least. So taking that data, we can
now look at say our cats, and UM measure whether
or not they are actually dreaming. And though it's obvious
to us, especially when they're twitching around and chasing mice
or whatever they're doing in the dream UM, but that
(08:17):
still doesn't necessarily answer why they are sleeping so much. UM.
So that's something that we can look at a little
bit closer. But I think within the case of our cats,
it may be that we've kind of done everything for
them and I'm going to go out all in here
because they don't necessarily have type from predators. They have
(08:38):
a food source, so they're all nice and cush you.
So it's some people say that maybe just that they
don't have, um, the impetus there too to be more
of a predator themselves and spend more time awake. Well,
certainly for indoor totally indoor cats that would be the case.
Are still goes outside and kills things and probably us
(09:00):
to avoid things every now and so. So that might
be why you're cat sleeping twelve hours and my cat
is landing around for sixteen hours. Oh yeah, it's kind
of like, hey, there's nothing going on here, I'm going
to go into the chipmunk dream. Yeah exactly. Yeah, it's
kind of boring here that or sometimes I think of
the movie Inception. Okay, sometimes I think that my cats
just kind of practicing to um put some sort of
(09:23):
thoughts in my subconscious when I'm make sure I'm dreaming.
They probably are. Is that is that crazy cat lady
talk a little bit? But I mean, you spend enough
time with a cats, those those guys are weird. Um
the thank you for comforting me. Well, the other thing
about cats and their predator nature. I've I've read some
some arguments that if society were fall apart um and
(09:44):
you know, in humans were gone the next day, like
you know, all the cats would obviously go feral. But
but domestic cats would have a better shot at surviving
as a species because they continue these rehearsals for you know,
for predation. You know, they're uh, they continue to even
if they're not hunting there, you know, they're attacking things
in your living room. You know, they're they're continuing the exercises.
(10:07):
It's like a constant terrorist training camp in your living room,
you know. Um, and and while dogs many breeds of dogs,
you know, it's like we'd be there, um you know,
perverted their natural hunting instincts into something ridiculous you know
where you know it ends up with we end up
like my parents, with a college that wants to bark
at trees, you know, and they don't really have us.
They don't have a skill set anymore. You know, they'd
(10:29):
be as useless as writers and the apocalypse. You know, wow,
but I don't know, I don't know writers could they
could do They could take their pencils. They don't even
use pencils anyone, am I saying, Yeah, you're right, they
would language with the dogs, they would begin barking in
the trees. Yeah, well I don't know. So we we
have animals that are clocking in a lot of sleep,
(10:53):
a little sleep. Yeah, yeah, they're they're kind of all
over the board. Like we mentioned the cat is coming
in it kind of like fifth half the day roughly.
And uh, and we should mention that you'll find varying
figures on all of this out there on the net
because you know, sometimes it's like a domestic animals sleep
or or you know, a captive animal sleep patterns versus
(11:14):
the wild animals sleep patterns. And you know, it's hard
to get a lot of sleep when someone is trying
to eat you. Yeah, that's true. And that makes sense
too because the ones that are captive, it's it's kind
of hard to measure some animals and and so yeah,
some of them would have to be captive in order
to get some data off of them, like um at
the like at the low end of the spectrum. Um,
(11:35):
Like it's hard to beat the giraffe, which is like
almost two hours a day and you know, which is
about seven point nine percent of the day. And uh,
and you see other like the horse is really low
at two point nine hours, the donkey at three point
one hours um. And which is kind of interesting because
I guess you, like some of these animals, you're thinking,
these guys are always on the run, you know, or
(11:56):
they've got to always be ready to to to you know,
to just take off at any moment to avoid a predator.
So they've apparently evolved, you know, into this state where
they just really don't need much sleep. Yeah, which I
thought was kind of odd because the giraffe I understood.
I thought, Okay, if I'm a giraffe and I'm you know,
out in the wild, I'm going to be scared that
(12:17):
something's got to you know, put its teeth into my
neck or or why not. But the cow not necessarily. Well,
I guess the cows one that we've it's kind of
like the dogs. We've really perverted the species over time
to where they're you know, they really don't have anything
to worry about. But maybe like some you know, original
version of the cow was more survival you know. Yeah,
(12:39):
this makes sense, Yeah, absolutely, And then I thought it
was really cool about the giraffe too. Is that they
sleep sometimes I get five minutes at a time. Yeah,
And and then they're really efficient sleepers, so they're not
kind of peddling around with the stage one and they're
not having dreams about tripping or you know, falling. They
get like straight into deep sleep, which I really admire.
(13:01):
I want to try to cultivate that for myself. Yeah.
They've Yeah, they've really just completely streamlined the process to
get right to the goods, the bare minimum to remain functional, insane,
I guess. Yeah. Yeah, they're like the Martha Stewart I
think of the animal Kingdom. They're just they're being very
efficient about how they spend their time sleeping. Well, you
know the the elephant that was pretty high up there,
and that's you know what's trying to eat an elephant? Yeah. Yeah,
(13:25):
and there is also the brown bat. Oh, the brown
bats on the the other end of the spectrum. Eighty
two point nine percent of the day, nineteen point nine
hours of sleep. Yeah, those suckers are I mean, they
are layabouts. Yeah, I mean you can think. The thing
I was reading about the brown bat is that a
(13:46):
their flyers and to fly with wings in this world
is it just requires a huge amount of energy. Like
that's why one of the reasons you don't have airplanes
with flapping wings because you know, it might look cool
in the uh, you know, in the sci fi movies
or the you know, the cartoons, but it would require
a tremendous amount of energy that just doesn't make sense
when you have propellers. Bats don't have propellers, so they
(14:09):
got a flap and by flapping, uh, you know, to
get things, you know, rolling in the air, they're expending
a lot of energy and they're eating like mosquitoes and stuff.
So sometimes the best course of action is to just
turn it off for nineteen hours. Yeah, and that would
make sense to you that they might hide themselves away
from predators or yeah, you know, or if the mascues
were only going to be out for a couple of hours,
(14:30):
you know. Yeah, that's right. Most of your bats are
seeking shelter in you know, high trees or in caves,
and they'll be in a situation where they really don't
have to worry about predators so much, either due to
their location or their numbers. Yeah. Another creature animal on
this list, um is the tree sloth, which is one
of my favorite animals. I think. Um, I don't even
(14:53):
know how to describe what it looks like other than
just like a hairy looking alien, ye, kind of a
mossy hairy alien, like a mumpy even too. I mean
it's like the Muppet that just didn't make the cut. Yeah,
you know, yeah, they kind of like somber face kind
of cute, like not the baby slots are really cute, obviously,
but we had the adults. They're yeah, they they're kind
(15:14):
of like Muppets. Yeah yeah, and it's maybe like it's
cute but menacing at the same time, which is I
think why it wouldn't have made the Muppet cut, you know.
But anyway, their their name Slaus obviously because um they're
thought of is well not just thought it. But they
are very slow moving creatures but um in captivity to
actually sleep for fourteen hours, but in the while they
sleep for ten hours, so that really mirrors more of
(15:37):
our own activity. Um. So I think just just I
can clear up their name a little bit because they're
already saddled with the Moniker slough. I just want to
get that out there for the sloth world. Yeah, a
little shout out. Now, Human infants are pretty high to
sixty sixty six point seven percent of the day sixteen hours. Yeah,
they're crazy high, which makes sense, um, because think of
(16:01):
I mean again, we got we've talked about the data
that you're processing during sleep, and just think of all
the stimuli. You know, you've been shut in the womb
for almost ten months. Yeah, like everything is new, lights different,
I mean yeah, some sound is familiar, but some sound isn't.
So it's uh, it's building that database that they have
to do. So I don't know. Um, are there any
(16:24):
creatures that require zero sleep for different types of sleep?
How does that work? Well, that's that's the question. Um,
I mean there are There are certainly animals that, for starters,
can disrupt their normal sleeping patterns for certain special events.
You know, like migratory birds. You know, they they've got
a suddenly put into overdrive travel long distances that they
(16:46):
can they can alter how much sleep they need. Um. Now,
fish and amphibians are these are some of the creatures
that were still not completely sure on whether they're sleeping
or not, or if they're just you know, exhibiting resting signs. Um.
And again the typical like signs of sleep. You know,
it's like you generally you're looking for reduction and physical activity,
(17:09):
discrete decreased response to outside sim stimuli um. And you
know generally that's you know, sleeping creature will will assume
a certain position, you know, or you know, back to
the cats, the same thing. Um. So we don't necessarily
observe these things going on with fish and amphibians. So
you know, the jury still is still out. So a
(17:30):
jellyfish could be like the way deep Bottom and they
might have successfully attached to tracking device, food or something,
and there's a period of inactivity, you sort of have
to assume that maybe they're in a resting state. Is
that Yeah, that that's kind of how it goes. But
again it's it's you know, it's like like you're saying earlier,
we base a lot of it on the on the
human mind, and we sort of, you know, we we
(17:50):
use that as the model to try and understand everything.
And you know, in some cases, like the jellyfish, I mean,
it's we're so distantly related that maybe it doesn't hold up,
you know, but right we're anthropomorphosizing everything. Now. One of
the really cool um areas of sleep is uni hemispheric sleep,
(18:11):
and you know, as in the hemispheres of the brain. Yeah,
and this is pretty good. It's kind of like, alright,
imagine you have a you have a company with ninety employees,
all right, and you're open nine to six, and then
then you decide, all right, we need to actually be
open all the time, you know. So so if you
came up so then you're like, all right, well, we
(18:32):
can't have all ninety employees work all the time because
they'll quit and leave or you know, riot or whatever.
So let's have like thirty work here, thirty work here.
You know, you end up like mixing it up. And
that's that's the pretty much what animals such as dolphins
and uh and you know another you know, aquatic mamalstude
because they're they're conscious breathers. So that's the other thing.
(18:54):
It's like, if they were to go to sleep, they
wouldn't breathe and then they would die. So they've got
to be awake in some fashion all the time. So
they just turn one hemisphere of the brain off. Is
it because there is it a function of their biology
or is it because they're worried about predators or both? Well,
(19:15):
there's that too. Yeah, I mean you're the the ocean
is an intensely dangerous place. You know, even if you're
you know, a dolphin hanging out with other dolphins and
you know they're you know, they're pretty rough and tumble characters,
but but still you know, there's constantly something trying to
eat you for the most part. So so yeah, that
what they do. It's kind of kind of like if
you've ever seen, uh, I understand, horses and some animals
(19:35):
still like or even like you know, joggers, I don't know,
will stand on one leg and rest the other and
then switch to the other leg and then rest that one.
It's the same thing except with the brain. So turn
one side off, let it rest. They'll let the other
side turn one side off and let it rest while
the other one powers everything and then do the do
the opposite. So you're never turning off both sides of
(19:58):
the brain and letting both sides eat it once, but
but one side of sleeping while the other remains awake.
So that allows you to react really quickly, just being
more efficient. Yeah, it's never a situation where um where
oh I've got awake, because uh, this is this actually
goes back to um to say, say you know, when
when you're asleep and suddenly you're you have a dream
(20:20):
where you're falling when you you know, fly awake. UM.
There are some interesting studies, UM, mostly from psychologist Frederick
Coolidge h And he's talked about this on Radio Lab
before I believe UM. Like, he argues that the the
idea of having a falling dream, UM, that comes from
like like early hominid history where we were living in
(20:43):
trees and when we were sleeping in the you know,
so you know, you're sleeping in a tree. That's kind
of you know, you're sleeping in a tree. So if
you fall out of that tree, there's you know, probably
all sorts of things just waiting, you know, for for
a little you know, eight creatures to plummet from the branches.
They can gobble them up. So if you feel like
you're falling instant away, because you've got to protect yourself,
(21:03):
you've got to grab back onto the tree and stay put.
So so they think that's like an evolutionary remnant of
those times. That's so cool for some reason, just reminding
you of my college dreammate who was constantly falling her
bunk bed, but like she fell completely off of it. Yeah,
I think again external forces acting on her. I think
she would have totally been eaten by wolves in the
(21:25):
old days. I know, I know her and Ozzy Osbourne, yeah,
both of them. Um. And like, I don't think I
ever get the the falling dreams per se, but I'm
I'm always getting these dreams where I'm like drifting off
to sleep a little bit, and then I'll dream that
I'm slipping on something like on a linoleum floor and
I'll be big and I'll just be like whoa, you know,
(21:45):
So that's funny. My mind is a sidewalk, which you know,
I don't know. I'm gonna see if I can lucid
dream next time and put a banana peel there or
something just to make a little bit more interesting. I'm
going to try that out. Um. But then anyway, back
to uh, back to the unihemistereric sleep. Um, it's a
it's it's hard for us, you know again, this is
(22:06):
us taking our you know, using our mind as the model.
It's it's difficult for us to imagine what this would
be like. But scientists think it might be some sort
of like a semi conscious state. Uh, what kind of
like we experienced when we're beginning to fall asleep. So
it would not be it would not be the same
as being awake. It would you would be operating everything
at half mast, you know, or half power, but but
(22:29):
you know, still awake enough to immediately respond to something.
There's no like, oh I think I'm falling, I'm gonna
wake up. It would be like there's a predator, I'm
gonna cut you know. So from my cat owen, I
have to say that I think I've actually observed this
in him before, where he's looking at me. This is
this is I think why cats get such a bad
rap sometimes and are called creepy. But he'll sometimes look
(22:49):
at me with one eye open and it'll be slightly
rolled back. So I knew that he's in some sort
of sleep state. So I have to wonder if it
also extends to other animals. Well, Um, this is an
interesting just in trying to figure out what euning hemispheric
sleep might be like. Um, there's a book called Consider
(23:11):
Fleebus by n And Banks. I don't know if you've
read anything by him. He's he's written a lot of
like just straight up fiction, like The Wasps Factory, and
he's a Scottish guy. He's also written a number of
sci fi novels and consider fleeb This was the first
book in the culture series, which is it's like a
space opera kind of thing, but he throws in a
lot of like really cool science and you know, in
(23:32):
philosophy and stuff like it. It's it's nice, you know,
brain fodder as far as sci fi goes. But in
this book, there's a character named Craiglin who has quote
enhanced hemispheric task division in his brain and uh and
the way it works out is that one that so
he's doing exactly what the dolphins do, but because he's
a dangerous mercenary and has to be you know, be
(23:53):
you know, on you know, alerted all times. So one
third of the time, though one of you know, one
half leaps and so he's a little bit dreamy and vague,
and then another third of the time he's all logic
and numbers and he can't communicate all that well with
other people. And then for the other third at the time,
he's completely awake. So so I found that really interesting,
(24:14):
like because obviously Banks was trying to imagine how unihemispheric
sleep would translate to the human experience the left and
right brain right, so right, So one part of us
would be really analytical and the other part would be yeah,
composing arias perhaps I don't know, Yeah, it would be.
It would be a weird life because you'd have to
it seems like you probably have to want to line
(24:35):
up and coordinate with your coworkers, with your spouse or
significant other, with you know, how you have You have
to really organize your life along which sleep pattern you were,
you know, which part of your brain was functioning. Well,
I think you'd have to actually color code yourself. I
think everybody would, because it's not one be just you, right,
it would be yeah, I'd be everybody one. So that
would be interesting. A world where everyone has unihemispheric sleep,
(24:58):
you'd have to be like like, oh, I can and
asked Julie about this right now, because obviously she's all
numbers and no speech, right, she's all green shirt today, Yeah,
forget it or green flag or whatever. Yeah. See, I'm
already trying to organize this. I'm really in training. But well,
we've got uni hemospheric sleep. Um. We also have something
called torpor, right, which is sort of a reduced version
(25:21):
of hibernation, and I think we should probably just mention
that because yeah, because people might be thinking, hey, how
about bears aren't sleeping for months? Not really right, right,
because they're they're taking their their bodies down to the
studs so to speak. I mean they're just shutting everything down. Um,
so there's not much brain activity there. But torpor is
sort of not as extreme version of hibernation, and that's
(25:43):
found in hummingbirds. Um. Yeah, yeah, we were talking about
this earlier and I believe it's uh yeah, they mentioned this.
I think in Aton Borrows the life of birds at
one point where humming we're talking about how much energy
it takes to fly, and hummingbirds are the extreme of this.
They just consume a colossal amount of energy. Yeah, their
heart it doesn't beats per minute or secondary. They're just
(26:06):
they're completely inefficient. And so when they go to sleep,
they actually seriously like knock themselves out pretty much. Um.
They hang upside down like a bat, and they they
sleep overnight. And this is actually called corporate because it's
not necessarily what we think of as sleep sleep. It's
just it's a letter version again of hibernation. And they
really but they need that time periods. Like you said,
(26:28):
they're not very efficient conserving their energy. So you could
go up to a hummingbird and just kind of tap
it and you might think it's dead and actually won't
even rant um. But that's how it's getting at seas.
And it's just kind of another interesting way to think
about sleep because I know at some point this is
sort of semantics. You know, we think about sleep, sleep, hibernation, torpor,
but it's all about just shutting it down. And there's
(26:51):
a reason why we do that, because you know, we've
we've got to get the benefits of sleep. Um, Yeah,
what's the payoff? What is what's Owen or in my case,
Biscuit doing all this time when they're well, I think
with with Biscuit and Owen, they're they're definitely um again
because they're not out in the wild there, maybe not
(27:11):
recharging as much as a human would um, but they're
definitely working through the data and they're processing and who
knows what. We don't know what they're dreaming about, but
like you said, they're they're really their skills are still intact.
You've gotta wonder if maybe they're still putting themselves through
the paces she said, I think it was like like
carrot cat terrorist attack training count. Yeah. Um, so they
(27:36):
may just be putting themselves through their exercises and jumping
through hoops and what not they do in dreams. But um. So,
one of the things that we know about sleep is
that it helps us to repair all the muscles and
the tissues. Um. And it also helps us to review
the data that we've taken in, and it makes us
more adaptive to the environment around us, because every day
(27:56):
you there's something new that you're taking in. I mean,
it could be you're driving to work and you see
some light, you know, dabbling a leaf, um, but you're
not necessarily really gonna dwell on that, so your brain
just kind of goes to MEUNI files it away, and
that might be something that it recalls later just as
part of a vast amount of data it has to
sort through. So I was thinking about this and I thought,
(28:17):
what is the most extreme version of the benefits like
who that we know that we can study, and that
would certainly be human infants because as we have mentioned,
they sleep up to sixteen hours a day and about
fifty percent of that time they're dreaming. So I mean
that's that's an organism that is working really really hard
(28:37):
at developing neural pathways and um, doing all sorts of
crazy things to try to get its body bigger faster.
It's mine bigger and faster. I mean the human mind
actually develops them in the first two years it's mass
so um, they're doing a lot of work there. So
I thought that was that's kind of a cool thing
(28:59):
to look at because if you compare it humans, human
adults are actually spending about of their time dreaming. So
think about the human infant. It's building up its own new,
fresh database. And you you take that sort of model
and you start to apply it to other forms. So
if you look at um, like there's a study that M. I. T.
(29:22):
Did with rats basically saying they were performing these repetitive
tasks and then they were sleeping and they were performing
them again and they were doing exceedingly well. And so
we know this in humans too, that you learned something,
you sleep and all of a sudden you're like, I
(29:44):
don't know, you're like canarieves and um, you're in the matrix. Uh,
and you know you're not that good, but but still
it's kind of late when people say like, oh, I
need to sleep on this. Yeah, exactly, exactly. And I
think was it um Roosevelt who just wouldn't make any
major decision without taking a nap, which I thought was,
you know, pretty great. Yeah. I think that he always
carried like a cot with him and it would be
(30:06):
in the middle of like you know, international conference and
they have someone asked him a question and be like,
I don't know if they plot the cot eight hours
later to have an answer. See, I kind of want
to do this at work. I don't know how well
it would go down, but you know, I think I
think it's worth a shot. Yeah. Um, you can try
to introduce that. And then you think about Paul McCartney
who who claims that Yesterday was written in a dream
(30:28):
and he woke up and just ran the piano and
got it down as quickly as he could. So if
you think about the benefits of sleep, and particularly for humans,
it's it's a it's a great place to repair your
body and also work through all the anxieties, fears and
hopes that you have in this sort of safe place.
So it's sort of like a blackboard of the mind. Um.
(30:49):
So if you apply that again, if you look at
the at the rats, you can see that the same
thing is happening in other species. That rats too are
taking data and running through it, and cats are and
they're coming out much better on the other end. So
it's kind of like just as our computers are running
their defrag programs at like three in the morning or
scanning for viruses, it's kind of the dream or dream cycle,
(31:11):
and our sleeper is achieving the same thing. Yeah, yeah, absolutely. Actually,
when I was looking a lot of this data that
I was thinking about, um, how much of this is
so similar to a computer, which makes sense because humans
if created computers, and it's sort of based on the
way that we say that, like maybe we didn't create well,
you know, you've got some you've got some other theories
(31:31):
blown around there. Yeah, I don't know if this is
the space one. But I'm not going to mention aliens.
I'm not. Um, But then you also have I think
it's important to also mentioned that not all creatures dream.
To reptiles, we don't think that they dream. I should
say that because yeah, I mean, come on, they've got
(31:52):
you know, primorial go in there. I don't know, um,
but they actually they're not exhibiting any sort of ways
that we can we recognize the streaming. So it may
just be that we're limited in what we can sense
in them, but I just think it's important for that
out there. Um. So we can really only theorize out
the benefits of animals. Obviously, obviously we can't go up
(32:14):
to them and say, hey, draft what, how is this
benefiting you? Um? But I think the difference between humans
and animals is that for animals, it's more about external forces. Um,
the they're reacting to their external forces. They're behaving that
in different ways. Um. Because of that. You know, we
sleep during the day, or excuse me, at night because
(32:36):
we work during the day. They don't have this sort
of pressures or concerns, and so they may be sleeping
when there's a predator around. So, um, we know that
they're benefiting from it because they they're not gonna get eaten,
so they're gonna you know, scroll themselves away, so to speak. Uh.
So that's a benefit to them, and it's and it's
(32:57):
something that we can theorize about. But again we can't.
We don't have any definitive answers on right now. We
can definitely deprive them of their sleep and see what happens.
And there's been a number of interesting slash scary studies,
um creepy studies about that. For instance, there was like
there's a Princeton University study in which they deprived number
(33:18):
of animals will sleep and they found it like seventy
two hours without sleep results in elevated stress hormone levels
and the animals end up producing significantly fewer brain cells,
which again flows right back into what we're talking about,
the processing of all the stimuli, the recharging you know,
of the of the you know, the the fleshy computer,
(33:40):
um and the computer. And they also found that like specifically,
like you know, we're talking about rats earlier, um, like
two weeks without sleep kill a rat dead um, And
same same thing with other rodents and uh and even
um even flies like you know, like I said, we're
not sure about all insects, but if like apparently there's
(34:02):
a they've tried to deprive flies of sleep and found
it flyestyve so, which makes sense. I mean, you know,
I'm sure you've pulled all nighter before. We all have
awful and if for some reason you did that two
days in a row, then your your cognitent functions are
like in a breakdown a lot, I mean you're an
after wear your your green shirt or whatever, like half
(34:25):
my brain is out. Yeah, and um, it's interesting. I've
also read that like there's like a specific gene that
like some people have, like you know that there there's
some people people that are like, if I don't get
my six to eight hours of sleep, I just can't
function and uh, and then other people seem to be
able to pull the all nighters with a little more finesse.
(34:45):
And there's there's like a genetic marker for that, uh
that they'veified. Yeah. I don't have the name of it offhand,
but we I think we mentioned in the previous podcast.
So it's not necessarily that they're lacking what what is
the gosh can't it's not coming to me right now,
But there's just certain I think hormone that um that
we have that helps melatonin, that regulates that. It's not
(35:05):
necessarily that they have a little or a lot in melatonin.
It's just that they've adapted somehow which are different you know,
just a different evolutionary you know adaptation. So it's one
of the things where if like you know, some sort
of space predator came down and started eating everybody that
couldn't pull all nighters. Then we'd all we'd only have
that one variation of humans left. So I think it's
(35:25):
good to know that. And I say that because I
think I read somewhere that Oprah only sleeps like six
hours a night, and I was like, wow, another way
in whichever is making me feel like, you know, I'm
not doing all that I should be. Yeah, I love you.
So the fruitfuly thing, it really kind of cracks me
up because I think, how exactly did they deprive them
(35:49):
of sleep? Yeah? I picture them just sort of poking
them in the shoulder like a little stick. Okay, I
was I was just thinking about these tiny little cigarettes
they might have fashioned, and some little cups of coffee
just keep them caffeinated and up. Yeah. Well that's that's
the Terrans. When they talk about the sleep these animals
like just being super stressed from not sleeping. It's kind
of like I would be really stressed too if like
(36:09):
somebody was making like preventing me from sleep, right you
know that? Would you know, what's this guy doing in
my room poking me with a stick all night, you know,
right enough with the tiny cigarette. That makes me think
of this too, is that I've heard that when you're
when you're really stressed out during the day, that that
does mess up your cortisol levels, which tend to peek
(36:29):
during the nighttime hours, which usually your circadian rhythms would be,
you know, stomping on that making sure that you you know,
that wouldn't be happening. So I'm just sort of fascinated
with that because I wonder if the same thing happens
in animals and their cortisol levels also go up, or
if that's just a particularly human thing. Yeah, I don't know,
(36:50):
like humans don't get enough sleep, you know that they
say at least, you know, a a degradation of the memory.
You can't you know, hold as many facts, your alertness,
level of coordination, judgment, everything kind of tumbles downhill. So
supposedly like Keith Richards stayed awake for like a week
once or something, so um, I never put him in
the same column with Navy seals, but now I am.
(37:11):
That's yeah, It's like I imagined in the whole team
of them, a whole team of Keith Richard's est Navy
seals sort of like stumbling into a secret hideout and
mumbling about well should haven't? Okay? That was that was
not good? Sorry about that? Well? So there you have it. Right,
That's that's pretty much animal sleep. So to all animals sleep,
A large number of them do. There's some we're not
(37:33):
sure about. But sleep does different things depending on what
your species happens to be. Yeah. Yeah, and we still
don't know what our cats are dreaming about. Um, we
want to know. We want to hear from you. Do
you what are your cats dreaming about something? Are they
trying to plant thoughts and your subconscious Yes, let us
know pretty much any thoughts you have about your cat's
(37:54):
brain activity, we would be happy to hear it. So Hey,
if you want to learn more about sleep and dreams,
be sure to check out the house stuff works dot
com website. We have articles like do all Creatures Sleep?
By Jessica Toothman. We got a couple of articles from
Charles Bryant, Sleep Important, Why do we sleep? And uh?
We even have how sleep works by Marshall Brain himself.
(38:17):
Thanks for listening for more on this and thousands of
other topics. Is it how stuff works dot Com? Want more?
How stuff Works. Check out our blogs on the House
stuff works dot com home page.
Welcome to Stuff to Blow Your Mind from how stuff
Works dot com. Hey, welcome to Stuff to Blow your Mind.
My name is Robert Lamb, and I'm a senior writer
here at how stuff works dot com. And with me
today is Julie Douglas, who is a longtime writer, editor,
pyrotechnician here at how stuff works dot com. Welcome to
(00:27):
the podcast, Julie, Thanks Robert, I'm really excited to be here. Yeah,
we're gonna be uh taking the podcast often an entirely
different trajectory now. You know, previously we were stuff in
the science lab. Now we're stuff to blow your mind.
It's kind of like a a joy division to new order,
Um Jefferson Airplane to Jefferson Starship kind of shift here.
(00:47):
It's you know, the old version was great, but the
new version is going to be even more amazing. That's right.
I mean we have everything from like our cat's shape
shifters to why are we existing here in this world?
In this universe? I mean, we're just gonna open the
portal and we're gonna start the new iteration. Yes, all right,
let's get this started. Yeah, let's do it. As it happens,
(01:10):
we are both cat owners so we are very familiar
with the site of a cat in its various stages
of sleep, which it seems like they have many, just
based on their their bodily position, right, It's true, they're elaborate. Sometimes.
I really love watching my cat in slumber, and I
look at him sometimes and think, oh my god, why
(01:30):
can't I be you? It just seems so like the
master of the universe here in your sixteen hours of
various positions of sleep. Yeah, we refer to them to
our cats sleep levels based on what kind of bread
product she resembles. So there's like bread mode where she
looks kind of like a loaf of bread, and then
of course when she gets really relaxed, she goes into
(01:50):
full on bagel mode, where she's like, you know, very circular,
kind of looks like a cinnamon bun. Wow. So, and
and they do sleep a lot. In fact, let's see,
what's the uh be terrible for cats? It's like fifty
point six percent of the day give or take leopards
of like twelve point one hours. Yeah, yeah, And I
would definitely say my cats more like maybe on the
(02:11):
sixteen hour. And he's seriously just doesn't do a whole lot.
And I don't know if that's because he's a main
con and he's like this twenty six pound um cat.
That's you know, like I said, the master of the universe. Um,
he can do whatever he wants. So if he wants
to sleep for sixteen hours, it's going to happen. It's
it's it's interesting because obviously most humans with you know,
(02:32):
jobs and and you know responsibilities, don't sleep twelve hours
a day. Um. Yeah, so it's more like in the
six to eight range. And you see a wide variety
of sleep patterns throughout the animal kingdom. So so yeah,
that's that's what we're gonna be chatting about today. Um,
you know, do all animals sleep? And what does that
consist of for different members of the animal kingdom? Yeah?
(02:54):
And why do our cats sleep so much? Yeah? That's
you know, I think that is actually a universal question
that has got to be as words. So we're going
to try to do that by first approaching sleep. Yeah,
what is sleep? Sleep? I think that obviously it's really important.
It is profoundly important on our existence and how we
operate physically, mentally, emotionally. Um, and I think that we
(03:18):
take it for granted but and we think, Okay, we
just close our eyes and we wake up and we
get going. Um. In fact, there's so much more going on,
and I think that we kind of need to revisit
the basics really quickly just to get an idea of
how complex sleep is. So you so let's just do
a quick recap. I'm sure we've all heard this in
school at one point or another, but you know that
(03:38):
there's stage one, which is the lightest sleep, and that's
when we kind of start to relax our muscles a
little bit. And is this the point where you're you're
reading your book at night and you suddenly start reading
words that aren't actually in the book. Yeah, they all
start to sort of melt together. And this is also
the point to where you feel like, well, they're like,
(03:59):
oh gosh, feels so great. You know that little voice
in your head I think, so I fallen asleep, that's awesome.
And then all of a sudden, you feel like you're
tripping or falling. Um, And that's really your muscles sort
of working themselves out. So that's stage one, and stage
two is when your breathing patterns and your heart rates
start to slow down a little bit. And your body
temperature takes a little bit of a dip. And then
(04:21):
stage three or when the delta waves start to roll
in and lull you into a deeper sleep, although you're
still sort of fighting with that lighter sleep. And then
stage four is known as the delta sleep, which, um,
it sounds like you should really say the adult asleep
because it you know, it's that really slow wave. Um.
(04:41):
And that's when you're getting thirty minutes of truly deep sleep.
And that is also when you're capable of sleep walking.
So yeah, So I don't know if you ever sleepwalked
when you were a little No, I don't think I did.
Know I did a lot, and so my parents would
see me cruising through the house like three am, and
my hands would be up like Frankenstein. So I literally
(05:03):
thought I was Frankenstein. I was rolling around the house
like that. But wait, in the dreams or just as
a child, you were convinced you were Frankenstein in the dream.
In the dream, yeah, I mean, because kids are weird,
I could you know, that's kind of awesome. I kind
of wish that I had been a kid who thought
that she was Frankenstein because I could really freak out
the neighbors and just dream fire. Um. That sounded like
(05:26):
Robert de Niro's Frankenstein. Sorry about that. Um. And then
stage five is when remickers. So that's when you're dreaming, um.
And that's when you're really working things out, all that
data that you've processed throughout the day. Um. And that's
also where you might be having a dream that's say
a dog is mauling your face, god forbid, and a
(05:47):
dog might be having a dream where it's mauling a
humans face exactly. Yes, yeah, and total totally parallel dreams
at the same time. And the cool thing about this
is that, uh, you have a sort of built in mechanism,
paralysis mechanism to make sure that you don't freak out
during that time period, so that dog doesn't leap out
and try to bite in its dream and I don't
(06:09):
try to you know, take the dog off of me
and smash it or interesting. So like that. So many
of these episodes you hear about where like somebody's having
a dream and they start like strangling their spouse or
something like you know, um, like that's not in this
stage then no, No, I think there's something else going on. Well, yeah,
because I think I'm probably thinking of Ozzy Osborne. So well,
(06:30):
you have to wonder too if there are certain medications
or substances that might be messing with the natural rhythms. Yeah,
I mean, I don't know that Azzy was ever on anything,
but no, no, yeah, I mean that's that's pretty far
fetched for him. But yes, so you never know. That's, um,
there's certainly external forces that could be acting on that. Okay.
(06:50):
So there, So we're in this stage, we're dreaming the
brains being cleared up, and we're going through these stages
about ninety minutes every ninety minutes, so there's a ton
of stuff that's going on, and we're also kind of
flailing around, moving around. I think I've read a stat
somewhere that we move around at least seven times per hour.
So it's not the it's not just the slumber that
(07:11):
we think of. That's all peaceful and you know, the
cats called up by your head. I need that staff
next time I'm kicked out of bed at three in
the morning from moving too much. Yeah, yeah, see that
that would be helpful maybe maybe, Yeah, I mean probably
can't like actually present the stats at three in the morning,
be like, whoa wait, slow down, check out this review,
this the study, and the Scientific American. I'm totally supposed
(07:33):
to move around. You should be concerned if I'm not
kicking you in my sleep, you know. Yeah, on second FID,
that might exacerbating the situation. UM. So it's good to
have an understanding of just what basically what sleep is,
because that's the model that we use UM to study
other animals, other creatures. We know about theta waves delta waves,
so you know that when they go into these slow
(07:54):
low wave states, that there that their brains are preoccupy
hid and that they're dreaming or sleeping, and that's what
we assume at least. So taking that data, we can
now look at say our cats, and UM measure whether
or not they are actually dreaming. And though it's obvious
to us, especially when they're twitching around and chasing mice
or whatever they're doing in the dream UM, but that
(08:17):
still doesn't necessarily answer why they are sleeping so much. UM.
So that's something that we can look at a little
bit closer. But I think within the case of our cats,
it may be that we've kind of done everything for
them and I'm going to go out all in here
because they don't necessarily have type from predators. They have
(08:38):
a food source, so they're all nice and cush you.
So it's some people say that maybe just that they
don't have, um, the impetus there too to be more
of a predator themselves and spend more time awake. Well,
certainly for indoor totally indoor cats that would be the case.
Are still goes outside and kills things and probably us
(09:00):
to avoid things every now and so. So that might
be why you're cat sleeping twelve hours and my cat
is landing around for sixteen hours. Oh yeah, it's kind
of like, hey, there's nothing going on here, I'm going
to go into the chipmunk dream. Yeah exactly. Yeah, it's
kind of boring here that or sometimes I think of
the movie Inception. Okay, sometimes I think that my cats
just kind of practicing to um put some sort of
(09:23):
thoughts in my subconscious when I'm make sure I'm dreaming.
They probably are. Is that is that crazy cat lady
talk a little bit? But I mean, you spend enough
time with a cats, those those guys are weird. Um
the thank you for comforting me. Well, the other thing
about cats and their predator nature. I've I've read some
some arguments that if society were fall apart um and
(09:44):
you know, in humans were gone the next day, like
you know, all the cats would obviously go feral. But
but domestic cats would have a better shot at surviving
as a species because they continue these rehearsals for you know,
for predation. You know, they're uh, they continue to even
if they're not hunting there, you know, they're attacking things
in your living room. You know, they're they're continuing the exercises.
(10:07):
It's like a constant terrorist training camp in your living room,
you know. Um, and and while dogs many breeds of dogs,
you know, it's like we'd be there, um you know,
perverted their natural hunting instincts into something ridiculous you know
where you know it ends up with we end up
like my parents, with a college that wants to bark
at trees, you know, and they don't really have us.
They don't have a skill set anymore. You know, they'd
(10:29):
be as useless as writers and the apocalypse. You know, wow,
but I don't know, I don't know writers could they
could do They could take their pencils. They don't even
use pencils anyone, am I saying, Yeah, you're right, they
would language with the dogs, they would begin barking in
the trees. Yeah, well I don't know. So we we
have animals that are clocking in a lot of sleep,
(10:53):
a little sleep. Yeah, yeah, they're they're kind of all
over the board. Like we mentioned the cat is coming
in it kind of like fifth half the day roughly.
And uh, and we should mention that you'll find varying
figures on all of this out there on the net
because you know, sometimes it's like a domestic animals sleep
or or you know, a captive animal sleep patterns versus
(11:14):
the wild animals sleep patterns. And you know, it's hard
to get a lot of sleep when someone is trying
to eat you. Yeah, that's true. And that makes sense
too because the ones that are captive, it's it's kind
of hard to measure some animals and and so yeah,
some of them would have to be captive in order
to get some data off of them, like um at
the like at the low end of the spectrum. Um,
(11:35):
Like it's hard to beat the giraffe, which is like
almost two hours a day and you know, which is
about seven point nine percent of the day. And uh,
and you see other like the horse is really low
at two point nine hours, the donkey at three point
one hours um. And which is kind of interesting because
I guess you, like some of these animals, you're thinking,
these guys are always on the run, you know, or
(11:56):
they've got to always be ready to to to you know,
to just take off at any moment to avoid a predator.
So they've apparently evolved, you know, into this state where
they just really don't need much sleep. Yeah, which I
thought was kind of odd because the giraffe I understood.
I thought, Okay, if I'm a giraffe and I'm you know,
out in the wild, I'm going to be scared that
(12:17):
something's got to you know, put its teeth into my
neck or or why not. But the cow not necessarily. Well,
I guess the cows one that we've it's kind of
like the dogs. We've really perverted the species over time
to where they're you know, they really don't have anything
to worry about. But maybe like some you know, original
version of the cow was more survival you know. Yeah,
(12:39):
this makes sense, Yeah, absolutely, And then I thought it
was really cool about the giraffe too. Is that they
sleep sometimes I get five minutes at a time. Yeah,
And and then they're really efficient sleepers, so they're not
kind of peddling around with the stage one and they're
not having dreams about tripping or you know, falling. They
get like straight into deep sleep, which I really admire.
(13:01):
I want to try to cultivate that for myself. Yeah.
They've Yeah, they've really just completely streamlined the process to
get right to the goods, the bare minimum to remain functional, insane,
I guess. Yeah. Yeah, they're like the Martha Stewart I
think of the animal Kingdom. They're just they're being very
efficient about how they spend their time sleeping. Well, you
know the the elephant that was pretty high up there,
and that's you know what's trying to eat an elephant? Yeah. Yeah,
(13:25):
and there is also the brown bat. Oh, the brown
bats on the the other end of the spectrum. Eighty
two point nine percent of the day, nineteen point nine
hours of sleep. Yeah, those suckers are I mean, they
are layabouts. Yeah, I mean you can think. The thing
I was reading about the brown bat is that a
(13:46):
their flyers and to fly with wings in this world
is it just requires a huge amount of energy. Like
that's why one of the reasons you don't have airplanes
with flapping wings because you know, it might look cool
in the uh, you know, in the sci fi movies
or the you know, the cartoons, but it would require
a tremendous amount of energy that just doesn't make sense
when you have propellers. Bats don't have propellers, so they
(14:09):
got a flap and by flapping, uh, you know, to
get things, you know, rolling in the air, they're expending
a lot of energy and they're eating like mosquitoes and stuff.
So sometimes the best course of action is to just
turn it off for nineteen hours. Yeah, and that would
make sense to you that they might hide themselves away
from predators or yeah, you know, or if the mascues
were only going to be out for a couple of hours,
(14:30):
you know. Yeah, that's right. Most of your bats are
seeking shelter in you know, high trees or in caves,
and they'll be in a situation where they really don't
have to worry about predators so much, either due to
their location or their numbers. Yeah. Another creature animal on
this list, um is the tree sloth, which is one
of my favorite animals. I think. Um, I don't even
(14:53):
know how to describe what it looks like other than
just like a hairy looking alien, ye, kind of a
mossy hairy alien, like a mumpy even too. I mean
it's like the Muppet that just didn't make the cut. Yeah,
you know, yeah, they kind of like somber face kind
of cute, like not the baby slots are really cute, obviously,
but we had the adults. They're yeah, they they're kind
(15:14):
of like Muppets. Yeah yeah, and it's maybe like it's
cute but menacing at the same time, which is I
think why it wouldn't have made the Muppet cut, you know.
But anyway, their their name Slaus obviously because um they're
thought of is well not just thought it. But they
are very slow moving creatures but um in captivity to
actually sleep for fourteen hours, but in the while they
sleep for ten hours, so that really mirrors more of
(15:37):
our own activity. Um. So I think just just I
can clear up their name a little bit because they're
already saddled with the Moniker slough. I just want to
get that out there for the sloth world. Yeah, a
little shout out. Now, Human infants are pretty high to
sixty sixty six point seven percent of the day sixteen hours. Yeah,
they're crazy high, which makes sense, um, because think of
(16:01):
I mean again, we got we've talked about the data
that you're processing during sleep, and just think of all
the stimuli. You know, you've been shut in the womb
for almost ten months. Yeah, like everything is new, lights different,
I mean yeah, some sound is familiar, but some sound isn't.
So it's uh, it's building that database that they have
to do. So I don't know. Um, are there any
(16:24):
creatures that require zero sleep for different types of sleep?
How does that work? Well, that's that's the question. Um,
I mean there are There are certainly animals that, for starters,
can disrupt their normal sleeping patterns for certain special events.
You know, like migratory birds. You know, they they've got
a suddenly put into overdrive travel long distances that they
(16:46):
can they can alter how much sleep they need. Um. Now,
fish and amphibians are these are some of the creatures
that were still not completely sure on whether they're sleeping
or not, or if they're just you know, exhibiting resting signs. Um.
And again the typical like signs of sleep. You know,
it's like you generally you're looking for reduction and physical activity,
(17:09):
discrete decreased response to outside sim stimuli um. And you
know generally that's you know, sleeping creature will will assume
a certain position, you know, or you know, back to
the cats, the same thing. Um. So we don't necessarily
observe these things going on with fish and amphibians. So
you know, the jury still is still out. So a
(17:30):
jellyfish could be like the way deep Bottom and they
might have successfully attached to tracking device, food or something,
and there's a period of inactivity, you sort of have
to assume that maybe they're in a resting state. Is
that Yeah, that that's kind of how it goes. But
again it's it's you know, it's like like you're saying earlier,
we base a lot of it on the on the
human mind, and we sort of, you know, we we
(17:50):
use that as the model to try and understand everything.
And you know, in some cases, like the jellyfish, I mean,
it's we're so distantly related that maybe it doesn't hold up,
you know, but right we're anthropomorphosizing everything. Now. One of
the really cool um areas of sleep is uni hemispheric sleep,
(18:11):
and you know, as in the hemispheres of the brain. Yeah,
and this is pretty good. It's kind of like, alright,
imagine you have a you have a company with ninety employees,
all right, and you're open nine to six, and then
then you decide, all right, we need to actually be
open all the time, you know. So so if you
came up so then you're like, all right, well, we
(18:32):
can't have all ninety employees work all the time because
they'll quit and leave or you know, riot or whatever.
So let's have like thirty work here, thirty work here.
You know, you end up like mixing it up. And
that's that's the pretty much what animals such as dolphins
and uh and you know another you know, aquatic mamalstude
because they're they're conscious breathers. So that's the other thing.
(18:54):
It's like, if they were to go to sleep, they
wouldn't breathe and then they would die. So they've got
to be awake in some fashion all the time. So
they just turn one hemisphere of the brain off. Is
it because there is it a function of their biology
or is it because they're worried about predators or both? Well,
(19:15):
there's that too. Yeah, I mean you're the the ocean
is an intensely dangerous place. You know, even if you're
you know, a dolphin hanging out with other dolphins and
you know they're you know, they're pretty rough and tumble characters,
but but still you know, there's constantly something trying to
eat you for the most part. So so yeah, that
what they do. It's kind of kind of like if
you've ever seen, uh, I understand, horses and some animals
(19:35):
still like or even like you know, joggers, I don't know,
will stand on one leg and rest the other and
then switch to the other leg and then rest that one.
It's the same thing except with the brain. So turn
one side off, let it rest. They'll let the other
side turn one side off and let it rest while
the other one powers everything and then do the do
the opposite. So you're never turning off both sides of
(19:58):
the brain and letting both sides eat it once, but
but one side of sleeping while the other remains awake.
So that allows you to react really quickly, just being
more efficient. Yeah, it's never a situation where um where
oh I've got awake, because uh, this is this actually
goes back to um to say, say you know, when
when you're asleep and suddenly you're you have a dream
(20:20):
where you're falling when you you know, fly awake. UM.
There are some interesting studies, UM, mostly from psychologist Frederick
Coolidge h And he's talked about this on Radio Lab
before I believe UM. Like, he argues that the the
idea of having a falling dream, UM, that comes from
like like early hominid history where we were living in
(20:43):
trees and when we were sleeping in the you know,
so you know, you're sleeping in a tree. That's kind
of you know, you're sleeping in a tree. So if
you fall out of that tree, there's you know, probably
all sorts of things just waiting, you know, for for
a little you know, eight creatures to plummet from the branches.
They can gobble them up. So if you feel like
you're falling instant away, because you've got to protect yourself,
(21:03):
you've got to grab back onto the tree and stay put.
So so they think that's like an evolutionary remnant of
those times. That's so cool for some reason, just reminding
you of my college dreammate who was constantly falling her
bunk bed, but like she fell completely off of it. Yeah,
I think again external forces acting on her. I think
she would have totally been eaten by wolves in the
(21:25):
old days. I know, I know her and Ozzy Osbourne, yeah,
both of them. Um. And like, I don't think I
ever get the the falling dreams per se, but I'm
I'm always getting these dreams where I'm like drifting off
to sleep a little bit, and then I'll dream that
I'm slipping on something like on a linoleum floor and
I'll be big and I'll just be like whoa, you know,
(21:45):
So that's funny. My mind is a sidewalk, which you know,
I don't know. I'm gonna see if I can lucid
dream next time and put a banana peel there or
something just to make a little bit more interesting. I'm
going to try that out. Um. But then anyway, back
to uh, back to the unihemistereric sleep. Um, it's a
it's it's hard for us, you know again, this is
(22:06):
us taking our you know, using our mind as the model.
It's it's difficult for us to imagine what this would
be like. But scientists think it might be some sort
of like a semi conscious state. Uh, what kind of
like we experienced when we're beginning to fall asleep. So
it would not be it would not be the same
as being awake. It would you would be operating everything
at half mast, you know, or half power, but but
(22:29):
you know, still awake enough to immediately respond to something.
There's no like, oh I think I'm falling, I'm gonna
wake up. It would be like there's a predator, I'm
gonna cut you know. So from my cat owen, I
have to say that I think I've actually observed this
in him before, where he's looking at me. This is
this is I think why cats get such a bad
rap sometimes and are called creepy. But he'll sometimes look
(22:49):
at me with one eye open and it'll be slightly
rolled back. So I knew that he's in some sort
of sleep state. So I have to wonder if it
also extends to other animals. Well, Um, this is an
interesting just in trying to figure out what euning hemispheric
sleep might be like. Um, there's a book called Consider
(23:11):
Fleebus by n And Banks. I don't know if you've
read anything by him. He's he's written a lot of
like just straight up fiction, like The Wasps Factory, and
he's a Scottish guy. He's also written a number of
sci fi novels and consider fleeb This was the first
book in the culture series, which is it's like a
space opera kind of thing, but he throws in a
lot of like really cool science and you know, in
(23:32):
philosophy and stuff like it. It's it's nice, you know,
brain fodder as far as sci fi goes. But in
this book, there's a character named Craiglin who has quote
enhanced hemispheric task division in his brain and uh and
the way it works out is that one that so
he's doing exactly what the dolphins do, but because he's
a dangerous mercenary and has to be you know, be
(23:53):
you know, on you know, alerted all times. So one
third of the time, though one of you know, one
half leaps and so he's a little bit dreamy and vague,
and then another third of the time he's all logic
and numbers and he can't communicate all that well with
other people. And then for the other third at the time,
he's completely awake. So so I found that really interesting,
(24:14):
like because obviously Banks was trying to imagine how unihemispheric
sleep would translate to the human experience the left and
right brain right, so right, So one part of us
would be really analytical and the other part would be yeah,
composing arias perhaps I don't know, Yeah, it would be.
It would be a weird life because you'd have to
it seems like you probably have to want to line
(24:35):
up and coordinate with your coworkers, with your spouse or
significant other, with you know, how you have You have
to really organize your life along which sleep pattern you were,
you know, which part of your brain was functioning. Well,
I think you'd have to actually color code yourself. I
think everybody would, because it's not one be just you, right,
it would be yeah, I'd be everybody one. So that
would be interesting. A world where everyone has unihemispheric sleep,
(24:58):
you'd have to be like like, oh, I can and
asked Julie about this right now, because obviously she's all
numbers and no speech, right, she's all green shirt today, Yeah,
forget it or green flag or whatever. Yeah. See, I'm
already trying to organize this. I'm really in training. But well,
we've got uni hemospheric sleep. Um. We also have something
called torpor, right, which is sort of a reduced version
(25:21):
of hibernation, and I think we should probably just mention
that because yeah, because people might be thinking, hey, how
about bears aren't sleeping for months? Not really right, right,
because they're they're taking their their bodies down to the
studs so to speak. I mean they're just shutting everything down. Um,
so there's not much brain activity there. But torpor is
sort of not as extreme version of hibernation, and that's
(25:43):
found in hummingbirds. Um. Yeah, yeah, we were talking about
this earlier and I believe it's uh yeah, they mentioned this.
I think in Aton Borrows the life of birds at
one point where humming we're talking about how much energy
it takes to fly, and hummingbirds are the extreme of this.
They just consume a colossal amount of energy. Yeah, their
heart it doesn't beats per minute or secondary. They're just
(26:06):
they're completely inefficient. And so when they go to sleep,
they actually seriously like knock themselves out pretty much. Um.
They hang upside down like a bat, and they they
sleep overnight. And this is actually called corporate because it's
not necessarily what we think of as sleep sleep. It's
just it's a letter version again of hibernation. And they
really but they need that time periods. Like you said,
(26:28):
they're not very efficient conserving their energy. So you could
go up to a hummingbird and just kind of tap
it and you might think it's dead and actually won't
even rant um. But that's how it's getting at seas.
And it's just kind of another interesting way to think
about sleep because I know at some point this is
sort of semantics. You know, we think about sleep, sleep, hibernation, torpor,
but it's all about just shutting it down. And there's
(26:51):
a reason why we do that, because you know, we've
we've got to get the benefits of sleep. Um, Yeah,
what's the payoff? What is what's Owen or in my case,
Biscuit doing all this time when they're well, I think
with with Biscuit and Owen, they're they're definitely um again
because they're not out in the wild there, maybe not
(27:11):
recharging as much as a human would um, but they're
definitely working through the data and they're processing and who
knows what. We don't know what they're dreaming about, but
like you said, they're they're really their skills are still intact.
You've gotta wonder if maybe they're still putting themselves through
the paces she said, I think it was like like
carrot cat terrorist attack training count. Yeah. Um, so they
(27:36):
may just be putting themselves through their exercises and jumping
through hoops and what not they do in dreams. But um. So,
one of the things that we know about sleep is
that it helps us to repair all the muscles and
the tissues. Um. And it also helps us to review
the data that we've taken in, and it makes us
more adaptive to the environment around us, because every day
(27:56):
you there's something new that you're taking in. I mean,
it could be you're driving to work and you see
some light, you know, dabbling a leaf, um, but you're
not necessarily really gonna dwell on that, so your brain
just kind of goes to MEUNI files it away, and
that might be something that it recalls later just as
part of a vast amount of data it has to
sort through. So I was thinking about this and I thought,
(28:17):
what is the most extreme version of the benefits like
who that we know that we can study, and that
would certainly be human infants because as we have mentioned,
they sleep up to sixteen hours a day and about
fifty percent of that time they're dreaming. So I mean
that's that's an organism that is working really really hard
(28:37):
at developing neural pathways and um, doing all sorts of
crazy things to try to get its body bigger faster.
It's mine bigger and faster. I mean the human mind
actually develops them in the first two years it's mass
so um, they're doing a lot of work there. So
I thought that was that's kind of a cool thing
(28:59):
to look at because if you compare it humans, human
adults are actually spending about of their time dreaming. So
think about the human infant. It's building up its own new,
fresh database. And you you take that sort of model
and you start to apply it to other forms. So
if you look at um, like there's a study that M. I. T.
(29:22):
Did with rats basically saying they were performing these repetitive
tasks and then they were sleeping and they were performing
them again and they were doing exceedingly well. And so
we know this in humans too, that you learned something,
you sleep and all of a sudden you're like, I
(29:44):
don't know, you're like canarieves and um, you're in the matrix. Uh,
and you know you're not that good, but but still
it's kind of late when people say like, oh, I
need to sleep on this. Yeah, exactly, exactly. And I
think was it um Roosevelt who just wouldn't make any
major decision without taking a nap, which I thought was,
you know, pretty great. Yeah. I think that he always
carried like a cot with him and it would be
(30:06):
in the middle of like you know, international conference and
they have someone asked him a question and be like,
I don't know if they plot the cot eight hours
later to have an answer. See, I kind of want
to do this at work. I don't know how well
it would go down, but you know, I think I
think it's worth a shot. Yeah. Um, you can try
to introduce that. And then you think about Paul McCartney
who who claims that Yesterday was written in a dream
(30:28):
and he woke up and just ran the piano and
got it down as quickly as he could. So if
you think about the benefits of sleep, and particularly for humans,
it's it's a it's a great place to repair your
body and also work through all the anxieties, fears and
hopes that you have in this sort of safe place.
So it's sort of like a blackboard of the mind. Um.
(30:49):
So if you apply that again, if you look at
the at the rats, you can see that the same
thing is happening in other species. That rats too are
taking data and running through it, and cats are and
they're coming out much better on the other end. So
it's kind of like just as our computers are running
their defrag programs at like three in the morning or
scanning for viruses, it's kind of the dream or dream cycle,
(31:11):
and our sleeper is achieving the same thing. Yeah, yeah, absolutely. Actually,
when I was looking a lot of this data that
I was thinking about, um, how much of this is
so similar to a computer, which makes sense because humans
if created computers, and it's sort of based on the
way that we say that, like maybe we didn't create well,
you know, you've got some you've got some other theories
(31:31):
blown around there. Yeah, I don't know if this is
the space one. But I'm not going to mention aliens.
I'm not. Um, But then you also have I think
it's important to also mentioned that not all creatures dream.
To reptiles, we don't think that they dream. I should
say that because yeah, I mean, come on, they've got
(31:52):
you know, primorial go in there. I don't know, um,
but they actually they're not exhibiting any sort of ways
that we can we recognize the streaming. So it may
just be that we're limited in what we can sense
in them, but I just think it's important for that
out there. Um. So we can really only theorize out
the benefits of animals. Obviously, obviously we can't go up
(32:14):
to them and say, hey, draft what, how is this
benefiting you? Um? But I think the difference between humans
and animals is that for animals, it's more about external forces. Um,
the they're reacting to their external forces. They're behaving that
in different ways. Um. Because of that. You know, we
sleep during the day, or excuse me, at night because
(32:36):
we work during the day. They don't have this sort
of pressures or concerns, and so they may be sleeping
when there's a predator around. So, um, we know that
they're benefiting from it because they they're not gonna get eaten,
so they're gonna you know, scroll themselves away, so to speak. Uh.
So that's a benefit to them, and it's and it's
(32:57):
something that we can theorize about. But again we can't.
We don't have any definitive answers on right now. We
can definitely deprive them of their sleep and see what happens.
And there's been a number of interesting slash scary studies,
um creepy studies about that. For instance, there was like
there's a Princeton University study in which they deprived number
(33:18):
of animals will sleep and they found it like seventy
two hours without sleep results in elevated stress hormone levels
and the animals end up producing significantly fewer brain cells,
which again flows right back into what we're talking about,
the processing of all the stimuli, the recharging you know,
of the of the you know, the the fleshy computer,
(33:40):
um and the computer. And they also found that like specifically,
like you know, we're talking about rats earlier, um, like
two weeks without sleep kill a rat dead um, And
same same thing with other rodents and uh and even
um even flies like you know, like I said, we're
not sure about all insects, but if like apparently there's
(34:02):
a they've tried to deprive flies of sleep and found
it flyestyve so, which makes sense. I mean, you know,
I'm sure you've pulled all nighter before. We all have
awful and if for some reason you did that two
days in a row, then your your cognitent functions are
like in a breakdown a lot, I mean you're an
after wear your your green shirt or whatever, like half
(34:25):
my brain is out. Yeah, and um, it's interesting. I've
also read that like there's like a specific gene that
like some people have, like you know that there there's
some people people that are like, if I don't get
my six to eight hours of sleep, I just can't
function and uh, and then other people seem to be
able to pull the all nighters with a little more finesse.
(34:45):
And there's there's like a genetic marker for that, uh
that they'veified. Yeah. I don't have the name of it offhand,
but we I think we mentioned in the previous podcast.
So it's not necessarily that they're lacking what what is
the gosh can't it's not coming to me right now,
But there's just certain I think hormone that um that
we have that helps melatonin, that regulates that. It's not
(35:05):
necessarily that they have a little or a lot in melatonin.
It's just that they've adapted somehow which are different you know,
just a different evolutionary you know adaptation. So it's one
of the things where if like you know, some sort
of space predator came down and started eating everybody that
couldn't pull all nighters. Then we'd all we'd only have
that one variation of humans left. So I think it's
(35:25):
good to know that. And I say that because I
think I read somewhere that Oprah only sleeps like six
hours a night, and I was like, wow, another way
in whichever is making me feel like, you know, I'm
not doing all that I should be. Yeah, I love you.
So the fruitfuly thing, it really kind of cracks me
up because I think, how exactly did they deprive them
(35:49):
of sleep? Yeah? I picture them just sort of poking
them in the shoulder like a little stick. Okay, I
was I was just thinking about these tiny little cigarettes
they might have fashioned, and some little cups of coffee
just keep them caffeinated and up. Yeah. Well that's that's
the Terrans. When they talk about the sleep these animals
like just being super stressed from not sleeping. It's kind
of like I would be really stressed too if like
(36:09):
somebody was making like preventing me from sleep, right you
know that? Would you know, what's this guy doing in
my room poking me with a stick all night, you know,
right enough with the tiny cigarette. That makes me think
of this too, is that I've heard that when you're
when you're really stressed out during the day, that that
does mess up your cortisol levels, which tend to peek
(36:29):
during the nighttime hours, which usually your circadian rhythms would be,
you know, stomping on that making sure that you you know,
that wouldn't be happening. So I'm just sort of fascinated
with that because I wonder if the same thing happens
in animals and their cortisol levels also go up, or
if that's just a particularly human thing. Yeah, I don't know,
(36:50):
like humans don't get enough sleep, you know that they
say at least, you know, a a degradation of the memory.
You can't you know, hold as many facts, your alertness,
level of coordination, judgment, everything kind of tumbles downhill. So
supposedly like Keith Richards stayed awake for like a week
once or something, so um, I never put him in
the same column with Navy seals, but now I am.
(37:11):
That's yeah, It's like I imagined in the whole team
of them, a whole team of Keith Richard's est Navy
seals sort of like stumbling into a secret hideout and
mumbling about well should haven't? Okay? That was that was
not good? Sorry about that? Well? So there you have it. Right,
That's that's pretty much animal sleep. So to all animals sleep,
A large number of them do. There's some we're not
(37:33):
sure about. But sleep does different things depending on what
your species happens to be. Yeah. Yeah, and we still
don't know what our cats are dreaming about. Um, we
want to know. We want to hear from you. Do
you what are your cats dreaming about something? Are they
trying to plant thoughts and your subconscious Yes, let us
know pretty much any thoughts you have about your cat's
(37:54):
brain activity, we would be happy to hear it. So Hey,
if you want to learn more about sleep and dreams,
be sure to check out the house stuff works dot
com website. We have articles like do all Creatures Sleep?
By Jessica Toothman. We got a couple of articles from
Charles Bryant, Sleep Important, Why do we sleep? And uh?
We even have how sleep works by Marshall Brain himself.
(38:17):
Thanks for listening for more on this and thousands of
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