Parrotfish Master Sleep Part 2 – Animal Sleep Secrets with Dr. John Lesku (Episode 42)

In this fascinating episode of Resilience Gone Wild, host Jessica Morgenthal speaks with Dr. John Lesku, a leading sleep researcher, about the amazing patterns and processes of sleep in animals of all types —and what they can teach us about human health, resilience, and performance. From parrotfish building mucus cocoons to sleep safely, to dolphins sleeping in with one eye and half brain alert, to penguins napping in microbursts, and birds sleeping mid-flight, this episode explores the incredible adaptations across species that allow sleep to happen in even the most challenging environments. Lesku discusses the latest sleep science, including how pollution and urban noise disrupt wildlife sleep, how sleep deprivation impairs cognition in both animals and humans, and why sleep hygiene is vital for long-term wellness. Together, they make a compelling case for rethinking our relationship with rest, emphasizing that sleep is not a luxury—it's a biological necessity.

Episode Transcript

(00:04):
Welcome to Resilience Gone Wild. I am Jessica
Morgenthal, and I'm here with my amazing producer,
Kai Sorensen.
Hello, everybody. Hello. Good to be here. And
we are just having the greatest conversation about
this amazing chat that we had with John
Lesku. And this, just to bring everybody to
this beautiful place that Kai and I are
in, was the topic of conversation,

(00:27):
the resilience tool that started this whole resilience
gone wild thing going. Really? Sleep?
It was the parrot fish's bubble. Oh, yeah.
This was one of the first episodes we
recorded. It was. And it was the first
thing I learned that I totally got blown
away by. So I was working and volunteering
in the marine life center, you know, in

(00:47):
Loggerhead, and I was teaching in the aquarium
section. And there was this amazing partner in
volunteering with that was helping me out, and
she was telling me about how these parrotfish
produce this entire bubble around them to protect
them to sleep. And it just blew me
away, and I it changed my whole mindset,
and it became all about the wisdom and
the brilliance and the resilience.
And then I couldn't stop thinking about it.

(01:08):
So this is how we all started. This
is kind of Yeah. I'm so, yeah, I'm
so glad you reminded me that,
that this was one of your launching points.
It was one of the first episodes we
recorded, oh my gosh, almost a year ago,
which is crazy. Season two coming up. But
I figured it took a while because you
wanted to find the perfect interview for this
Exactly. Yeah. Episode. And I and we did
find that doctor John Lesku.

(01:30):
And it's funny. His bio at the La
Trobe University website is, and I quote, I'm
interested in most things related to sleep. Yeah.
That's just And he's the sleep expert of
animals. Like, he the knowledge that this guy
has
developed from research and from learning from others
and from just being in such deep connection
with nature and with animal species is is

(01:53):
just kinda crazy. So, you know, he gives
us all these fun stories, and you can
just see how much this means to him.
And and Yeah. And that so excited to
share it.
Yeah. And it's so fun when you meet
people like this who are so deeply happy
with with the work they do. Like us.
For something yeah. Yeah. Like us. For something
that could feel so, like, I don't know.

(02:13):
It's like breathing. Right? But if you actually
think about it, it can have an effect
on your life in a profound way. And
as someone who is navigating life with a
a toddler, you know, sleep is very important,
and lack of sleep,
is is gosh. It can be can be
difficult. So Yeah. We take it for granted.
And if everybody's listened to the episode that
leads up to this around the parrot fish's

(02:35):
brilliant sleep tool and has hopefully learned something
about building yourself a bubble and creating an
environment that
that doesn't have distractions, it doesn't have predators,
and it doesn't have parasites
so that you can get that quality sleep
that you really need to to do what
you love in life. Yeah. And I think
as I've as I think more about, you
know, my sleeping habits, it's the phone's the

(02:57):
big one.
I would say
half the time, I'm able to leave my
phone in a place that's not reachable. And
I must admit, it does feel like I'm
moving the Titanic. Right? That is there's some
habits you're breaking. And I I think I
I am noticing
they're
a more refreshed sleep when I'm not, you
know, scrolling with some blue light. And and

(03:18):
I think for us, it's I think we're
getting and you'll remember this as a mother.
And when your kids get to a certain
age like Miles, he dropped an explicit word
in context
the other day. Where did he get that
from?
Exactly. So
context clues are becoming really important for my
wife and I in term modeling behavior. Right?
So being careful on our phones, what is
a good sleep schedule? And it's so funny.

(03:40):
My wife and I always joke about how
I would love for someone just to give
me a bath,
read me some books, and put me to
bed by seven,
and then wake up at seven the next
day. Right? To be two. Right? There's some
really nice things about being two again. So,
anyways, there's a lot lots to discuss, and
we won't waste any more any more time.
We'll get to that interview. But the people

(04:00):
have been listening, Jessica. New reviews are rolling
in,
and we gotta read one. So out there,
again, please take time to stop rate review.
It really helps us in this algorithm
chaos to get this message of resilience to
people who need to hear it. So, we
got a five starrer from Sharon
Danziger.
Did I say that right? Do you know

(04:21):
her? Alright. If you're interested in nature, the
planet, positive psychology, climate change, and resilience, you
will love, all caps, this podcast. I'm so
impressed by amount of science research Jessica
includes in each of her podcast episodes and
weekly newsletter, folks. Make sure you subscribe to
that almost weekly when we have the time.
I particularly love how she connects resilience in
nature to small, actual steps we can take

(04:42):
to build resilience and help the planet. You
won't be disappointed.
She also has a lovely voice to listen
to. I agree as someone who has edited
Many in an episode. My hun I know.
I have to say, Sharon, thank you so
much for leaving the review, Sharon. I'm a
huge fan of this fabulous woman I met
recently, and she has just, you know, has
this this super positive energy about resilience gone

(05:03):
wild. And given all of the amazing work
that she does, I am honored by I
love to hear that, and we love the
support. And I just heard my toddler get
home. So before his footsteps are in the
recording, let's get to the interview. Let's get
to the interview. Have fun.
Hey, John Blescu. I am so unbelievably excited

(05:24):
that you're here to share this discussion with
me, and I usually start with a yay,
so yay, you're here with me.
And just to sort of put it all
together, you are in Australia
at early in the morning, being quiet to
to be,
care for your children's sleep, which is so
relevant to this conversation, right? Like protecting our

(05:46):
sleep, which is the sleep bubble that we
have on Parrotfish, and the alarm has not
yet gone off for them and probably won't
because it's school vacation time. And It's the
evening for me, it's early morning for you,
and I am so, so joyful that you
heard to share this with time of the
day. So we're here because we
Parrotfish
Sleep Bubble actually started me out on this

(06:06):
entire journey because I fell in love with
the idea that there was this metaphor
around
putting a bubble around yourself as a resilience
tool for sleeping better. Fast forward like nine
months, and I found like the perfect person
to talk to about animal sleep and to
just get into this, like, really joyful conversation
and really helpful resilience conversation. So just a

(06:30):
bit about John, then we're going to ask
him to introduce himself. Traveled the world studying
sleep, you know, America, Canada, Germany,
not only Alaska, but the northernmost tip of
Alaska, right?
Yeah, that's right. So
to you, John, like, just tell us a
little bit about why and where and what

(06:50):
drove this incredible
passion for animals in sleep?
Yeah. Thanks, Jessica. I'm really happy to be
here.
So I've been studying sleep
in animals with really special emphasis on nonhuman
animals
since 02/2003.
And I guess the reason I got into

(07:10):
this was I did an undergraduate degree
in zoology,
the University of Guelph in Canada.
And I was kind of disappointed in some
ways at the end of that zoology degree
that you would take subjects in
animal behavior,
comparative physiology,
you know, evolution, ecology, histology,

(07:33):
all sorts of things. And yet, at the
end of it, you didn't actually talk about
how humans spend one third of their lives.
And in some animals, sleep is actually the
dominant state, and they spend more than 50%
of their lives asleep. And yet, this wasn't
discussed at all in any subject. And so

(07:53):
I left left university a little disappointed and
then decided I want to understand
what sleep is doing and what is the
diversity of sleep across the animal kingdom. So
then went down to Indiana,
to Terre Haute, Indiana,
to work on to start my journey on
sleep and animals, which, yeah, then took me
to to Germany and some field work in

(08:14):
exciting places. And now I'm at La Trobe
University in Melbourne, Australia.
You haven't picked up the Australian accent yet.
Have your kids?
Yeah. My kids sound like cartoon characters. Yeah.
It's true. But, no. My Canadian accent has
been really, really resilient to to infiltration
by this weird Aussie accent.

(08:35):
I love it. So it's so interesting because
we don't pay attention to the third of
our life, should be a third of our
life, right, that we are
just ignoring. I mean, it's literally a third
of our lives and more and less in
animals, and, like, what do we why do
we think that's not important? It's incredible.
So just to, like, process that, that, like,

(08:55):
we need to pay more attention to a
third of our life
and
how how the nonhuman or the more than
human world spent a third of or more
of their life.
Yeah. That's I I agree. It's it's a
strange thing. So if you live to be,
you know, say, 75
years of age, then you'll have spent the
equivalent of twenty five years of that time

(09:17):
in this state of sleep. And yet sleep
typically isn't given much thought. If anything, it's
sometimes even given derision
that if you if you prioritize your sleep
and you say, oh, I wanna
sleep in, or I I stayed up late,
I need to sleep in the next day,
then you'll be perceived as as lazy, as

(09:37):
weak.
You won't be hardworking.
So, yeah, it's it's a bit of a
pity that society takes this view, and yet
sleep is
getting an adequate amount of sleep. Not too
much, but getting eight hours a night or
seven to eight hours a night is considered
one of the main pillars of a healthy
lifestyle that there's getting enough exercise, having an

(10:00):
appropriate diet, and getting seven to eight hours
of sleep a night. So if you don't
have a problem happens while you're asleep. Right?
Like, you're not intentionally making it happen, but
your body and your mind and are a
super powered action
during the night, like all kinds of amazing
things happen, and I want you to share
that about what happens in our bodies as
humans and more than human bodies, and it

(10:22):
just occurred to me that like, I volunteered
at a turtle sea turtle hospital, and no
one ever talks about
what happens
when the lights you know, when everybody leaves
at 05:00 or 05:30, and then they come
in the next morning at, you know, at
06:30.
What's happened there? I mean, I know the
vet must have a sense because once in
a blue moon, you know, they'll dry dock

(10:43):
a turtle because they don't
they aren't sure that they'll have enough energy
to, like, pick their head out of the
water or something.
Otherwise,
like, it's so important,
and I gotta make sure I get them
talking about it.
So, anyway, just hope So so sleep is
serving
lots of different
processes. And when we talk about these processes,

(11:04):
I must admit the caveat
that we really only understand them in a
handful of species.
So it is a question mark whether we
can generalize these to all mammals,
all birds, all animals,
or if this is specific to a human,
a rat, and maybe a pigeon, you know.
So with that caveat in mind, because we're

(11:25):
always limited by data across lots of diverse
species, sleep is doing lots of things and
it's doing them simultaneously.
There is not a single function of sleep,
but there are many processes. So for instance,
one of the
the main hypotheses for the function of sleep,
which is probably insulting to it because it's
more of a a fact really, is that

(11:47):
sleep is rescaling the connections in your brain.
So during the day, which I guess is
the end of the day for you, your
brain will be more interconnected
individual brain cells or or neurons by an

(12:09):
integrated hear more about this. What does interconnected
mean in this conversation?
Yeah. Yeah. And how does it change over
the course of the day?
Yeah. So so your your
neurons in your brain, they talk to each
other with these connections that are synapses,
these chemical connections. Hello? And,
and these connections,

(12:30):
if you use them more while you're awake,
they become stronger
just by being used. And, this is Captain
Marbles, by the way. Hi, Captain Marbles. He's
a big cat. He is, and he's a
he's a feature of my online lectures as
well. He's part of this then. He is.
Yeah.
And so those synapses, they become stronger. This

(12:52):
is a process called synaptic potentiation,
if you like jargon. But they just become
stronger, and that's a really good process because
it is the it is the cellular basis
by which you learn information. In order to
learn, your brain needs to change. So it's
great. It's great. It's how you learn,
but it's not sustainable

(13:12):
day after day after day. You need a
process that checks that increase in the strength
of synapses,
and one sleep function is to reduce the
strength of synapses
in your brain
so that at the start of the next
day, your brain is now refreshed and ready
to take in more information. That's not to

(13:33):
say that you forget
during sleep. It's just to say that that
if you use connections more while awake,
then those connections
are going to be relatively
stronger the next morning
relative to other connections that weren't used that
day. So all that happens at night. Idea.
So, like, if we you know, I always,

(13:54):
I have this conversation with people all the
time, they say so and so has a
better memory than somebody else or than they
do, and I challenge it and I say
that's because they tell the same stories
over and over again and build those neural
networks like over and over again, and it
never occurred to me
that sleep was part of that, that that
had to be clear, you know, that stuff

(14:16):
gets cleared out at night that's not really
used, and that the stuff that is used
over and over again gets built stronger and
stronger during sleep. So if I'm not sleeping
enough or people aren't sleeping enough, what is
the impact? If you don't sleep enough,
then so there's a really classic study from
the nineteen nineties, and it makes the effects
of sleep loss really accessible. So in this

(14:39):
study, they took human
volunteers, and
they how to start this one. And they
kept them awake for twenty four hours.
And then over those twenty four hours, they
had them do a hand eye coordination task
on a computer screen. And, of course, within
the normal sixteen hour day that we all
experience, performance was very high on this task.

(15:02):
You do great during that sixteen hours. But,
of course, if you extend the amount of
wakefulness another eight hours, then performance declines across
that time. Super low. Lighting being the same.
You're not turning the lights off at night.
Just That's that's right. Yeah. That's right. It's
just a function of the time that they've
spent awake.
And then in a separate study,

(15:22):
they didn't sleep deprive them, but they gave
them alcohol. And so the more intoxicated
they became, of course, their performance also declined.
And at a certain level,
when they reached the legal legal level for
intoxication,
which here is is point o 8%. I
don't know what it is in Florida. But

(15:43):
point o 8%,
blood alcohol concentration
resulted in a very low level of performance,
unsurprisingly.
And if you Is that where they came
up with that number, by the way? Yeah.
Yeah. No. No. It's not from this study.
It's not from this study. No. I mean,
in general, is it from studies that show
the reduced capacity?
I hope so. Right? Okay. Average reduced capacity,

(16:05):
yeah, across across humans.
And if you take that, you know, their
performance level at the legal level of intoxication,
and you look at when did the sleep
deprived group achieve
that low level of performance,
well, they did,
and they did it when they had been
awake for twenty four hours. So by extending

(16:26):
your waking day
by eight hours,
results in your hand eye coordination to the
level of someone legally intoxicated.
Wow. That's just something worth processing. Right? Like,
you do the same damage to your capacity
from just not sleeping for one night
than you do by being legally drunk and

(16:47):
and not allowed to drive.
Yeah. Or or use equipment or whatever. Right?
And it is true that very rarely in
your life, I suppose, will you achieve twenty
four hours of wakefulness. Maybe on a long
haul international flight, you might do it. Or
if you have a baby, you could
imagine a lot of new parents are not

(17:07):
performing their best. However, sleep restriction,
that is to say, you're still sleeping, but
instead of getting eight hours
a night, you're getting six hours a night
or four hours a night.
There are cumulative
effects of having
restricted
sleep
over days. So if you get, say, six
hours of sleep a night for two weeks,

(17:28):
and at the end of that two weeks,
you will still be performing as poorly
as the drunk people were in that study.
And so the people always say they make
up sleep on the weekends or whatever. Can
you undo that by oversleeping?
How do you fix it? You don't actually
fully recover by just having one,

(17:49):
ad libitum sleep. It does take a few
days. So sleeping in Saturday morning is not
going to undo two weeks of restricted sleep,
if that's what you are getting. That's what
I was getting at.
So the best thing that you can do
is really just try to maintain what's called
good sleep hygiene, which is getting seven to
eight hours of sleep a night. Each night,

(18:10):
having a regular
bedtime, avoiding caffeine in the evenings, avoiding screens
in the evenings, or at least using the
night shift feature to have more amber light
in the display than blue light, which is
more
light, which is more disruptive of some hormones
like melatonin that promote sleep. And so having
a good sleep hygiene is key to maintaining

(18:30):
optimal performance while awake. Okay. I'm gonna put
it out there. I sleep, like, six hours
a night if I'm lucky in general. Is
BB always here, oh, people who don't need
as much sleep, people who need more sleep.
What's the truth and reality of all that?
Yeah. So I think that,
by and large, modern sleep research probably does
people a disservice

(18:50):
by insisting
too heavily on seven to eight hours of
sleep a night because anxiety
causes sleep disturbances, and the proliferation
of technology
like smartwatches and things like this that track
your sleep and then you wake up in
the morning and it says, oh, maybe next
time you didn't get enough. I don't think
this really does us any favors because then

(19:12):
the next night you're going to be feeling
more anxious about getting more sleep, which might
interfere with your actual ability to do it.
So although on average, humans function best at
seven to eight hours of sleep a night,
but
if you're able to do well and maintain
a good quality of life,
and you sleep six hours a night, I

(19:34):
would certainly not say you're doing it wrong.
I think that we have to acknowledge that
there's differences between people, and if it works
for you, then do it. But if you
feel
tired during the day, well, then you have
a problem. Your body is sending you a
message.
Exactly. Just listen to what your body is
telling you. So let me ask you before
we get to animals, because I do wanna

(19:55):
talk about sleep animals so much. When we
talk when I think about when we think
sleep bubble and parrot fish and this amazing
capacity they have to protect their sleep, go
with that metaphor. What comes to mind when
you think about, you know, what we need
to protect on our sleep, what we need
to keep out, you know, you just talked
about blue light versus amber amber light. And
so, you know, the metaphor I went with

(20:16):
was, you know, the bubble keeps things out
and keeps things in. So what's coming to
mind?
Yeah.
So my lab works a good amount
on the way pollution affects sleep and wildlife.
And it's not all that we do, but
it's one of the main pillars of the
lab.
All different types of pollution, like light, sound,

(20:38):
and drama as well? Yeah. We work on
artificial light and noise, different wavelengths. We work
on urban noise, traffic noise, and we work
on psychoactive pollutants
that permeate
urban waterways. We can talk about that that
later if if you wish. And so in
the cases of Are you talking about, like,
medications, psychological medications that end up in the

(21:00):
water? Is that what you're saying? Indeed. So
so, you know, we're a well medicated society,
and we have well medicated urine, And we
pee that out, and it's not actually removed
effectively from water treatment. And it is dumped
as wastewater
into urban streams and waterways. There have been
global surveys about psychoactive contaminants

(21:20):
in waterways across every continent now, including Antarctica
near bases. And these suites, dozens and dozens
and dozens of different drugs
are detected
admittedly at extremely low concentrations,
concentrations that are not bioactive in people, but
are bioactive
in life that is inhabiting these waterways, and

(21:42):
it affects their sleep as well. But to
get back to your question about, you know,
about bubbles, the real problems we face in
our sort of technologically driven society
is mostly related to chemicals like overindulgence
of caffeine and alcohol, the permeation of bedrooms
by artificial light. Typically, these come from screens

(22:02):
that as you fall asleep, you're watching something
on a laptop, on a television, or on
a phone. And these are not great ideas.
Of course, this is an easy thing to
say and to recommend, but it's harder to
do that. And I'm guilty of this myself,
that you should be turning these things off
in the evenings. You should not be consuming
caffeine or alcohol close to bedtime. For caffeine,

(22:23):
it should be no later than two in
the afternoon. For alcohol,
around dinner time because these things interfere with
your ability to maintain the continuity of sleep.
Okay. So those are the things we need
to keep out.
And I go to a place of also,
you know, and it sort of relates in
some ways to the psych the
psycho something you said drugs,
all the

(22:44):
anxiety and other thoughts that are keeping you
up or or waking you up, you know,
that that we need some tools to get
out before we go to sleep.
You know, I offer things like journaling and
and,
ways to fall asleep and whatever. Do you
have some thoughts on given your history of
sleep research, some thoughts on

(23:05):
tools that you might use or that you've
heard of that to keep keep this crap
out of the bubble
for the night?
So speaking personally,
my crap manifests as emails on my phone
that I'm a habitual email checker. And so,
my solution has been to turn off the
ability to check and receive emails on my

(23:26):
phone. So I can't look at these things
because if, of course, if it's near bedtime
and I get an email, I'm going to
read that email. I'm going to think about
its consequences, what are the answers, what are
the action items that come out of that,
and this is going to keep me up
now. My mind is gonna be spinning on
this when it's not helpful for it to

(23:47):
be doing that. So that is the one
minor thing that I have changed to protect
my sleep
is turning off emails. Yeah. And it sounds
like that was the key for you, so
it's not really minor. It might be minor
for other people, but there's there's your the
advice, like, find a key thing that is
interfering with your sleep, and it can be
unique. It could be different from from everyone

(24:09):
else in your household or whatever, and own
it. Do something to say you are not
that important. The world will go on.
And you need your sleep because you won't
be of any value or enough value the
next day. Right?
That's right. That's right. And and I would
just add another quick thing here
that,
you know, the modern world is pretty cruel

(24:30):
to night owls, I would say. So, you
know, there's two basic so called chronotypes
of people. They're put into two broad categories.
The night owls that like to stay up
late and sleep in in the morning, and
there's the morning larks that like to do
the opposite.
Unfortunately,
I'm a night owl, and my partner, sadly,
is not.

(24:51):
And then there's the, you know, society is
really geared towards waking up, you know, 07:00,
being ready for school drop offs or starting
work at 09:00.
And the poor night owls suffer from this
because we're not
aligning our lives with our genetics. And this
is genetically

(25:12):
determined whether you're a night owl or a
morning lark. Society
is is pretty mean
to the to the night owls. And so
if your partner stays up late and doesn't
mean they're a party animal, and if they
wanna sleep in, doesn't mean they're lazy. It
just means that they're adhering to their genetics
and their biological clock.

(25:33):
Is there any connection between, like, nocturnal creatures
and
daytime creatures in in that genetics, or is
that
just a This is a you know, the
spectrum of humans?
Yeah. As far as I know, this is
a this is a human polymorphism
in a particular clock gene. Whether or not
animals have the same same variances, I assume
that they would, but I I don't know

(25:54):
of studies exploring.
Interesting. So to that end, let's switch a
little bit over to animals. And I did
some research on all of the amazing things
that are going on in your laboratory and
the research that you've done and that others
are doing, which spans
unbelievably
across
species and from birds to fish to mammals
to insects to like, really cool to be

(26:16):
able to have researched and do research on
such a mass, massive variety
of our
non human world, and to be able to
compare those and understand them, and the research
I imagine is so incredibly interesting and challenging
to like study the sleep behavior of a
bee versus
a bear or whatever,
and it turns out you study

(26:38):
Tasmanian devils, which is super cool because I've
got some episodes dropping about Tasmanian devils. I
did an interview with Dean Reid of Assiorek
last week, so like that's, I definitely wanna
hear about
the devils, but anyway, So Yeah. Go for
it. Tell us a little bit about what
comes to mind. Yeah. So the lab works
on
a few different main questions, I suppose, you'd

(27:00):
say. And so one of those questions, probably
the broadest one, is how does sleep evolve?
How does sleep change from different types of
animals? And so to answer this question,
we look at the sleeping brain activity of
birds
and mammals. And within mammals, we also study,
marsupials

(27:21):
Since I moved to Australia, we also study
bony fish. We study cartilaginous fish. We study
sharks and we study invertebrates
like, flatworms and weird things. And so that's
to get an understanding about how did sleep
first appear and how has it changed since
then. We're also interested, as I mentioned, about

(27:41):
different forms of pollution. We find ourselves living
in this geological period that's informally called the
Anthropocene,
a period that's marred by profound environmental change,
rapid environmental change, and animals need to get
their sleep too, living in the modified landscapes
that we have created for them.
So we study those various forms of pollution
that I talked about on on different kinds

(28:03):
of animals.
And again, that gets to the same problem
that humans have, right? Like we have light
pollution, we have sound pollution, some of it
we create ourselves, some of it is created
outside of our control, and that's one of
the issues, like what can we control, what
can we not control?
There are animals that burrow into, I assume,
deep dens to sleep because they're trying to

(28:24):
avoid all of that pollution and be in
a con in a closed bubble.
Yep. And,
like, I just get so this whole LED
bulb
change has been it just blows my mind
that people think it's okay because it doesn't
cost that much to keep an LED bulb
on, so they leave it on all night,

(28:45):
you know, like Yeah. There's
nature's being destroyed by all this. Like, their
sleep behavior is being destroyed, right? That's right.
And and not just their sleep behavior, but,
you know, it it changes it changes, of
course, their their brain activity is as well.
So,
if you were to, you know, we we've
brought in different birds into captivity and we've

(29:06):
simulated
environments that that look like street lights. And
these these lights, they mimic the intensity,
the light spectra of streetlights that you would
find in your own
neighborhood.
And when you give birds
the same lights, it halves the amount of
sleep that they get underneath those
lights, and they do try to compensate. They

(29:28):
do try to nap during the day, which
might have its own problems in the wild,
but they are sleeping about 50% as much
as they otherwise would. And in changing
the wavelength of that light towards amber colored
lighting, reddish orange y colored lighting. This is
a purported
savior
of sleep in circadian rhythms because it's less

(29:50):
disruptive
to the secretion of the sleep promoting hormone,
melatonin,
which is why your
technology and your phones will shift towards amber
light in the evening as an attempt to
minimize the disruption
of light in the evening on melatonin.
And if you give that to some birds,
like Australian magpies,

(30:11):
amber light, you find that amber light is
indeed less disruptive to the sleep of magpies.
It's still disruptive,
but it's less disruptive.
So that's a good thing for Australian magpies.
Okay. So magpies are super smart. Right?
Yeah. Magpies are phenomenal birds. We have we've
worked with them. It's another thing as a

(30:31):
non sleep related thing that the that the
lab works on. We work on cognition
Mhmm. Mostly in Australian magpies. So if you
don't know what it is, it is it
looks kind of like a crow. Mhmm.
And crows are members of this family, the
Corvidae or the Corvids,
which are really smart birds. Yes. Well, Australian

(30:52):
magpies, they look like Corvids, but they're not
corvids. They're a different family called chrysetids
and, the butcher birds.
And they're all over Australia. I'm sure there's
some in the backyard right now. And a
lovely bird, and we've done a variety of
cognitive tests on them and find that some
evidence that they might use tools, they might

(31:14):
use wooden sticks to pull food towards them
just as corvids will. They seem to be
able to understand causal reasoning in the sense
that in the sense that if you tie
a piece of string
to a food reward, well, they'll pull that
string to get the food. But then if
you cut a string so that it's no
longer functional, pulling one end no longer pulls

(31:36):
the food towards them, they will learn to
avoid
that string. It's amazing. I actually wrote a
post about magpies for April's April Fools' Day.
Do you have April Fools' Day in Australia?
Yeah. Yeah. Yeah. Yeah. And because they're actually
quite clever and funny. Like, they'll ring somebody's
doorbell
just to see what the reaction is and
like they're

(31:57):
characters, so what happens to them, like given
that they have an intelligence level, you know,
nearing what we think our intelligence level is
or maybe surpassing,
what happens to them? I mean, now that
you're you're studying them when it comes to
a loss of sleep, that's such a cool
thing that you've that you can see their
reactions in there. Yeah.
Yeah. So we've looked at the consequences of

(32:18):
sleep loss for Australian magpies. And if you
if you keep a magpie
awake for, say, six hours in the night,
and then you get them to perform cognitive
tasks the next morning, so these are fairly
simple cognitive tasks. So imagine you have two
wells
in front of you, and one has a

(32:39):
purple lid, and one has a blue lid,
and there's always a food resource under, say,
the purple lid. This is called associative
learning. You learn to associate
that a purple lid always has food underneath.
It's like the simplest form of learning that
you can imagine. And then there's once the
animal has learned that rule, purple equals food.

(33:02):
Well, you change that rule and you see
how quick is the animal to learn a
new rule. So maybe now food is under
blue, and this is a measure of behavioral
flexibility. How quickly can they switch to adopting
the new rule? And that's called reversal learning.
And then there's things like spatial memory you
can test, where the animals have not two
options, but they have 10 options, and they're

(33:24):
all blue lids now.
And the bird has to remember under which
lid the food actually was under.
A tech game called with the ball and
the three,
you move the ball around and you gotta
find the ball with the gambling game? Oh
my god. It would be kind of like
that, right? That's the idea behind it. But
if we stick to sort of the simpler
the simpler kinds of of learning, just just

(33:46):
associative learning, the simplest form, if they lose
six hours of sleep, actually their sleep is
not particularly impaired.
Their performance on the task is not particularly
impaired by that, which is a good thing
for magpies,
but perhaps it's just simply too, too
simple a task for them to do. Maybe
it doesn't matter if I've slept or not.
I can still tie my shoes, and maybe

(34:07):
this is the equivalent of tying the shoes
to the magpies. But if you keep them
awake for an entire twelve hour night, well,
then things do change.
So that's the level of wakefulness experienced by
that that that
the equivalent of an intoxicated human, you know,
awake for twenty four hours. And if you
do that to a magpie, well, now, unsurprisingly,

(34:28):
they're less likely to interact with the test
because they're prioritizing their sleep. But when they
do interact with the test, they make more
errors. So sleep does have a consequence for
their performance, but really only when
it is it is a very long duration.
Now that's occurring over a single night, and
remember I did say that in humans Yeah.

(34:48):
There is a cumulative effect of restricted sleep,
and we've never looked in a bird about
how does
does sleep restriction
night after night after night ultimately affect their
performance after, say, two weeks. But over the
course of a single
sleepless night, the birds do fare worse just
as a human would.

(35:09):
Yeah. Which makes sense, right?
It makes sense. Actually, I was reading something
about yours that even
animals
that don't have brains, like sea slugs,
have a need sleep. Like, just talk about
how does every single non human
creature, including plants, I want to ask you
about that, you know, fungus, fungi, plants, all

(35:32):
of it. Who needs sleep? I think sea
slugs have, like, a simple brain, like a,
like a ganglia, cephalic ganglia, but I'm not
too sure. But the simplest answer to your
question is that all species that have been
studied by sleep scientists have been found to
sleep. So, of course, this includes mammals, birds,
and other vertebrates, but then within
invertebrates,
which make up the majority of animal life

(35:54):
on the planet Yeah.
Sleep has been found in a variety of
arthropods,
like fruit flies, honeybees,
locusts,
cockroaches,
spiders,
crayfish.
Sleep seems to be common in arthropods and
presumably
everywhere, although we don't know for sure, of

(36:14):
course, because we've only studied, you know, 10
different species. And I say we, I don't
mean my lab. I mean, I mean the,
the field.
Sleep is also found within mollusks like garden
snails, cephalopods,
including octopus
and cuttlefish. It's been shown in nematode
roundworms.
It's been shown in platyhelmint

(36:34):
flatworms,
and within the Which are very low on
the evolution scale, right? Like, that was why
you you were starting to you you use
them as one of your research
studies? Yeah. So they're so flatworms are really
simple
in simple animals. So they lack a circulatory
system.
They lack an anus.
They they rely

(36:56):
they have no respiratory system. They rely on
simple diffusion for most things. And so really
simple animals, they do have a brain and
they have a need for sleep, but, they
don't have much else. And in the case
of the simplest animals that have been studied,
not by my group, but a group in
California,
is the cnidarians,

(37:16):
a group that includes jellyfish, sea anemones, and
coral. And within that group, upside down jellyfish
were the first cnidarian
to be shown to have a need for
sleep.
So as you said, these these animals, they
don't have a centralized nervous system.
They don't have a brain. They do have
a diffuse nervous system, this nerve net that

(37:39):
spans out into their radially symmetric bodies. There's
also been work on hydra,
these sessile polyps that, grab things out of
the water column with their tentacles.
They sleep as well. And how do you
tell if an animal is sleeping versus one
that's, you know, just inactive? Well, there's a
very simple

(38:00):
behavioral
assay that has been used for a hundred
years to determine this. It's really straightforward. So,
yeah, in most cases,
in most cases, a sleeping animal is going
to be, well, restful. It's going to have
a period of inactivity. That's not so surprising.
But the other features of sleep are that

(38:20):
they have reduced responsiveness.
So if I were to tap you while
you're awake gently,
well, you're going to respond quickly to that
tap. If I give the same intensity of
tap while you're asleep, well, you're probably going
to not detect it or require more taps
or stronger taps. So you have reduced responsiveness.
And in the business, we call this an

(38:42):
increased arousal threshold, but it just reflects that
you're less aware of the local environment.
And the same is true for jellyfish as
well. A jellyfish that's inactive at night is
going to take greater intensity stimulation
to respond. But then once they've responded,
if you then test them a second time,
well, they respond quickly because you've now woken

(39:03):
them. It was reminds me of two stories
that I wanna throw at you. My kids,
when they were younger, we used to have
an alarm system in our house, and it
would and it would go off by mistake,
you know, like a false alarm of some
sort, which would say intruder or fire or
something when there wasn't one because that stuff
happens. And my husband and I would wake
up, like, literally fall out of bed, and

(39:23):
we'd go into the kids' rooms and they'd
be fast asleep, right? I spoke.
They would wake up in a second. Your
body somehow or your brain is alert to
completely different things. And I recently heard a
story about a lion,
a lioness who went to was sleeping. The
safari
jeep was watching them, and they they had
this lioness had a sense that there was

(39:45):
no danger from this human, this type of
human, and she would sleep calmly
right next to the Jeep, but then she
heard the bell of a Maasai warrior
that is a human that still attacks lions,
and she woke up and took off like
like she'd been shot.
How do we manage and and be more

(40:06):
intentional about
protecting ourselves from
sleep that shouldn't be disrupted by certain things
that we're letting it disrupt us by?
Yeah. So what you're describing is is known
as sensory gating. So, you know, we're both
awake right now, presumably,
and the flow of information from our eyes,

(40:27):
our ears, our senses of touch, and taste,
Well, we receive these senses from the environment.
They're processed
at different levels within our brain.
Some are superficial levels, but some are higher
order processing centers within our brain. And that
series of steps results in a behavioral

(40:48):
output and I respond.
So during sleep, just in the case of
those lions, there's sensory gating.
So
the in the external world is still detected
at a superficial
level, but but a behavioral output is
is
is truncated.

(41:09):
There is not the signals do not reach
these higher order cognitive processing centers. Filtering. I
I mean, it's basically filtering, right? So it's
like a mother who hears the baby.
Exactly. Yeah. So the the processing information is
stemmed early on in the in the process.
It's kind of like if your if your
awake brain
is a is a castle,

(41:29):
And during the day, all of the drawbridges
are down, and information can move into the
center of the castle. But during sleep, the
drawbridges
come up. So information makes it to the
wall, but it doesn't get too deep into
the castle. And that was the case with
the lion. But if you have stimuli
that is very, very important and it would

(41:49):
be lethal for you to ignore, or not
even lethal, but in the case of humans,
if I were to this is gonna sound
creepy. Apologies. If I were to whisper your
name to you while you were sleeping, say
Jessica, Jessica, you're more likely to risk to
wake up to that
sound of whispering your name relative to to
me saying Kevin
next to you. Amazing. Right? And so you

(42:11):
do have an ability during sleep to distinguish
between different sounds and to respond to sounds
that your brain deems more important.
Which is why we can sleep in urban
locations
through all kinds of crazy urban noise, and
then people who
go take a vacation from an urban center
to the country

(42:31):
can't sleep because of the crickets and the
whatever, right, and vice versa.
So I think it's really important to recognize
this whole,
sensory gating,
right? You said that
we need to be aware of changes in
noise, and how do we get used to
a new a new
sound or light or any sense that we

(42:53):
want to have a gate for? Is it
just just taking it just takes time? Yeah.
That's right. So so your experience
matters. So we have a paper that's not
published yet, but we're about to submit for
review. I'm hesitant to mention it now that
I say it, but anyway, I will. And,
it's valid either way.
It is. And and in this study, we

(43:14):
wanted to see how does experience
change your the disruptiveness
of noise played to you at night. And
so we took, pigeons.
This was in collaboration with Sue Ann Zoellinger
at, Manchester Metropolitan University in The United Kingdom
and
took pigeons,
chicks, nestlings, pigeon nestlings, and reared them in

(43:35):
a room with urban noise that that people
might experience at night. And this was the
soundscape
of the city of Munich in Germany. And
those nestlings were then either exposed to urban
noise during
weeks as they were nestlings
or
a quiet room in which all they heard
was the ventilation system and the cooing of

(43:57):
other pigeons. And so so they had very
different upbringings.
And then as adults,
we looked at their sleep
in response to urban noise. And if you
were reared in a noisy
room as a chick, then as an adult,
your sleep was not impacted
by this urban noise playback. But if you

(44:18):
were reared in a quiet, that rural environment
that you were talking about, then as an
adult,
you
are bothered much in the same way as
our Australian magpies were to urban noise. You
have a, you know, almost a halving of
your sleep.
So I guess you just have to get
used to it. It takes time. That's right.
So so yeah. Which is probably a good

(44:38):
good story, actually, for urban wildlife is that
these animals persist in this environment just as
we do, and they probably can do so
because they're used to it. So their brains
have gotten habituated
to the noise and maintains the continuity
of sleep in the sky. I feel better
about that, that eventually, like, all this lighting
will be able to be ignored, how we're

(44:59):
going with that, and the sounds? I think.
Yeah. I mean, it is a very popular
thing to always say pollution is bad for
x, y, and zed, and I'm sure that
is true in many cases.
But I do feel like that
saying that ignores the obvious, which is these
animals have been here for a hundred years

(45:20):
or more
living in these modified environments with us,
yet they are still here. So, sure, it
might be bad relative to them living in
a nice forest somewhere, but the advantages to
them living in the city
seem to outweigh any costs to disruptive sleep
that they might Like, how so I don't

(45:41):
lose any sleep about Earth and the Earth's
loosens.
That makes me feel better. Pollution, not so
much. Okay. So I was just looking on
my on my list of notes because you
mentioned you have a new paper coming. You
also have a new book coming out.
Yeah. Right? Yeah. Yeah. Somniozoology,
I think. Is that what it's called? Somniozoology.
Yeah. That's right. Sleep Across the Animal Kingdom.

(46:01):
So tell us about your book and tell
us some of the stories, like, you have
some fun stories that, like, how do birds
and dolphins, this unihemispheric,
I assume that some of this cool stuff
that we are gonna be blown away by
the way some animals sleep, so share a
couple of wild things that we'd be surprised
at. Yeah. So
this is the

(46:21):
first book ever to talk to focus exclusively
on sleep in in nonhuman animals. It's all
about the amazing things that animals can do.
And the hope with the book is that
it really challenges us to view our view,
which is a very human centric view about
sleep. Obviously, we all have our personal experiences

(46:42):
with sleep, but when you look across the
animal kingdom, you find that animals have some
amazing adaptations
to permit sleep in the weird and wildest
of locations. And I would just mention that
this book is written with, Barrett Klein, who's
at the University of Wisconsin
in La Crosse, and Niels Rattenberg
at the Max Planck Institute for Biological Intelligence

(47:02):
in Germany and and myself. And so it's
Somnozoology
Global. Across the animal kingdom. It's global. That's
right. Yeah.
And we've the three of us have worked
together for a number of years, and we
felt that it was time to to combine
efforts
into writing this book. It's produced by published
by Harvard University Press and should come out
either at the end of this year or

(47:23):
the beginning of next. But, yeah, so you
mentioned marine mammals and some birds, and how
do they sleep? And
so, cetaceans, including dolphins,
some kinds of seal, manatees,
they can all sleep with one half of
their brain at a time, a state that's
called unihemispheric
sleep, half brained sleep. And then so when

(47:45):
they do this, obviously, half of their brain
is asleep. But then also that sleeping hemisphere
is neurologically
connected to a closed eye, which means that
the awake hemisphere is neurologically connected to an
open eye. So in sleeping unihemispherically,
these,
half brained animals can also maintain

(48:05):
half eyed awareness of the local environment and
seemingly able to respond to threats. They use
that open eye adaptively.
Dolphins will use their open eye to look
at other dolphins as if they're maintaining
cohesion of the pod as they swim. In
the case of frigate birds, frigate birds asleep
Those are the cool ones with the huge,

(48:26):
red thing hang hang up there. Yeah. Yeah.
The males. The males have this throat sack.
Yes. And great frigate birds are the only
bird that we know of that can sleep
in flight, and they sleep well soaring over
the open ocean. And as they do so,
they can sleep bi hemispherically
just as you and I do for short
periods of time. But they can also sleep

(48:46):
like a dolphin and can sleep with one
half of their brain at a time. And
what they're looking at is they're keeping their
eye open for other birds that are sleeping
in the same thermal as they are so
they don't collide midair.
Amazing.
What about all the other birds that are
taking these huge long migrations? How are what
are they doing to

(49:07):
to be able to get We actually don't
know. There are lots of different birds that
engage in multi night, sometimes multi week migrations,
or in the most extreme case, you have
swifts. And swifts, once they leave the nest,
they go up in the sky, and they
will stay there until it's time for them
to make a nest and to produce their

(49:28):
own chicks. They do not land again outside
of the breeding season.
And so presumably,
a swift is sleeping
on the wing, but we actually do not
know
Yes. How and and when yet how and
when swifts are sleeping. If you then go
beneath beneath the waves, there are some kinds

(49:49):
of sharks
that don't stop swimming. So great whites, bull
sharks, whale sharks, and rays.
Don't stop. These are all, so called ram
ventilating species. So they have to maintain forward
propulsion.
They keep their mouths open, and by swimming
forward, they force oxygenated seawater over their gills.
And if they stop swimming, they will drown.

(50:11):
And so we don't know how sharks such
as those are able to sleep well continuously
swimming. Do they have they evolved some kind
of unihemispheric
sleep like a dolphin,
or or how do they do it? We
we actually don't know the answer to that
question either. So there are still mysteries that
we have. Okay. So tell us some other
interesting stories. Like, what do you got that

(50:31):
just totally cracks you up that,
you were blown away by? So in 2023,
a group in in France led by a
gentleman named Paul Antoine Liberale, he had published
a great study looking at sleep in,
in penguins in Antarctica.
And,
he,

(50:52):
so was recording brain activity from these birds
using sensors, not unlike the sensors that would
record your brain activity in a sleep clinic.
And,
he
found that,
the penguins
would have about eleven hours of sleep a
night, a good a good amount of sleep
for a penguin, presumably.

(51:12):
And but the surprising thing is is that
they were having 10,000
sleep episodes
in that in that twenty four hour day.
And so how were they achieving eleven hours
of sleep? They were doing it by having
extremely short sleep bouts, one to four seconds
long.
And if you add up all of those
one to four seconds, you then get to

(51:33):
eleven hours.
And so this is one of these great,
reveals
about the diversity of sleep across the animal
kingdom that we consider
sleep fragmentation to be a bad thing. If
you have a partner who has sleep apnea,
you know, sleep apnea is where you wake
up hundreds of times

(51:53):
in the night,
just for a a millisecond
to regain control
over your
over the the tone in your windpipe. You
inhale, you go back to sleep. You're probably
not even aware of it.
And and and that's a pathology
in in humans.
And so sleep fragmentation
is is viewed as a bad thing

(52:14):
for humans.
But if you look in the in in
penguins, they don't seem to be bothered at
all. In fact, that seems to be what
they normally would be doing in nature. While
they're swimming or while they're hanging out in
the Well, they're in the colony. Well, they're
hanging out in the colony. Yeah. On the
shore.
On the shore. Yeah. They're on the shore
during during this time. You know? And another

(52:35):
another remarkable thing that some animals can do
is we studied,
the sleep of pectoral sandpipers
in Alaska, the North Coast Of Alaska. So
these are
a type of shorebird.
Outside of the breeding season, they're found in
the Southern Hemisphere. They're found in Australia, New
Zealand, and South America.

(52:55):
And then they they fly, take a multi
month flight, so not continuous. They stop plenty.
They take a multi month flight north from
the Southern Hemisphere
to above the Arctic Circle to breathe. Amazing.
So, like, one of the coldest places, which
is so weird, right, just to think about
it, but that's a separate issue. Yeah. But
but it also has, attractive things that it

(53:18):
has continuous daylight,
during this time, and the Arctic in the
summer becomes
hyperabundant
for food, particularly
for
soft bodied invertebrates living
in the
above the permafrost
in this sort of boggy soil. So it's
great for waders. So so a lot of
birds go to the High Arctic in the

(53:39):
summer to breed.
And so we followed the birds up. We
flew by airplane. We didn't do it the
hard way. And,
and when the birds arrive,
in the tundra,
the male set up territories because the males
are competing for access to females.
They want to impress females because the females

(54:01):
are extremely choosy about which males they're going
to mate with,
because the the the female has flown, what,
13,000
kilometers, something like that. Gonna make it worth
her while.
That's right. That's right. She wants to pick
the best male to sire what will be
the only clutch of that season.
So she really discriminates

(54:22):
among the boys.
But the boys are are are less discriminating
of the females. They want to mate with
as many females as they can because their
investment into reproduction is limited
really to to to sperm production, basically, and
and and
and defending their territories.
So the males, they set up these territories.

(54:44):
They have to fight other males, they have
to display to females, they have to look
out for predators,
and they have to eat.
And we found that some males, not all,
some males have a remarkable
capacity
to sleep very, very little for weeks
at a time. And when I say very
little, I mean, they could be awake 95%

(55:06):
of the time for three weeks.
And so this is a level of sleep
restriction,
extreme sleep restriction,
that a human could not endure for a
day or two without compromised performance. And in
the case of these sandpipers,
the males that are sleeping the least
are the ones that are able to convince

(55:28):
those those,
scrutinizing
females that they're the best male
to sire her only clutch of the season.
They ultimately produce the most chicks. And so
in this environment, sleep loss can be adaptive,
which was the first time that that had
been demonstrated in any animal.
That's amazing. It's the survival of the fittest

(55:49):
is the ones who can sleep who can
be sleep deprived the longest in this specific
species.
That's right. Okay.
Last words of wisdom. What do what do
you recommend? Or the how many hours sleep
did you get last night, by the way?
Okay. Okay. Now so according to my watch
this morning, I got over ten hours of
sleep. Now but there's a there's an important

(56:09):
caveat here is I just returned from Liverpool
in The UK. It's a long flight.
Horribly, horribly jet lagged after my, like, forty
hours of travel. Okay, that's fair.
So I slept a lot last night. But
you're making up for it. It's a good
thing.
That's right. That's awesome. We have to do
it tonight too. Awesome. Any any last words

(56:30):
of wisdom for us and other than the
fact that we need to go out and
buy your book and and read your articles
and and learn more about sleep?
That's right. I think I think that it
is it is fascinating to see the adaptations
that other animals have to get their daily
amount of sleep or, in the case of
the sandpipers,
not. There's real value in exploring this to

(56:51):
opening our eyes in a sense about what
sleep can be across the animal kingdom.
Yeah. So that we can respect them and
that we can learn from it ourselves.
So, yeah, awesome. Thank you so much, John.
So appreciate it. So happy after all this
time of waiting for somebody who's just the
right person to talk to about parrotfish and
and their sleep bubble. I so appreciate your

(57:12):
being in in this conversation, and, looking forward
to staying in touch and and keeping up
with your beautiful work.
Cheers. Thank you very much for the opportunity,
and thank you.

(57:35):
This has been a production of BLI Studios
produced by me, Kai. Follow along with our
other BLI produced shows at balancinglife'sissues.com/podcast-BLI.
Got an idea for the show? Email me,
Kai, at balancing life's issues dot com. And
don't forget to stay in touch with your
host, Jessica, at [e-mail].

(57:55):
Anything else to add, Miles?