March 13, 2017 • 17 mins
and is in such high demand that tons of it are being stolen from beaches. White rhinos use middens as a complex communal message board. Plus, clinical trials need more volunteers -- we explain why.
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:00):
Welcome to How Stuff Works Now. I'm your host, Lauren Vogelbaum,
a researcher and writer. Here at How Stuff Works. Every week,
I'm bringing you three stories from our team about the
weird and wondrous advances we've seen in science, technology, and culture.
This week, sand is in such high demand and construction
markets around the world that people are stealing tons of it.
(00:24):
And unrelated, it turns out that white rhinos communicate via
massive communal poop piles. But First, Senior editor Katherine Whitborren
and our freelance writer Alia Hoyt take us behind the
scenes of medical research. Clinical trials make amazing new treatments
possible and safe, but here in the United States, they
struggle to find participants. Here's why and what you can
(00:47):
do to help. Dave Bexfield of Albuquerque, New Mexico, was
diagnosed with multiple sclerosis in two thousand and six. Three
years later, he applied for a clinical trial sponsored by
the National Institutes of Health that involved a stem cell transplant.
Bexfield says the trial saved his life. Within a few
months of completion, in twenty ten, he could walk again
(01:09):
without a cane or a walker. Participation levels in clinical
trials are often very low, even for patients with terminal diseases.
Doctor Julie M. Vos, immediate past president of the American
Society of Clinical Oncology, told us that only about three
percent of adopt patients with cancer participate in clinical trials.
This low rate limits patient access to new interventions that
(01:31):
could treat or even cure their cancer. In fact, analysis
of cancer trials found that a whopping forty of them
were unable to enroll the minimum number of participants. Another
survey showed only thirty five percent of Americans said they
were likely to enroll in a clinical trial. So why
don't more people participate in trials, even if it might
save their lives? Here are some reasons. Number one, they
(01:53):
don't know what's available. People diagnosed with diseases often mistakenly
assumed that their doctor will suggest appropriate clinical trials if
they're out there. Although some physicians are very dialed into
ongoing research, many aren't or simply don't have time to
sit through all the opportunities for their patients. So in
addition to asking your doctor directly about clinical studies, you
can also check a number of online resources that can
(02:14):
help you find them. The National Institute of Health website
lists several databases, including clinical Trials dot gov, which allows
users to search by condition or location. Breast Cancer Trials
dot org is another disease specific option where you can
be matched with an appropriate study. Search for finding clinical
trials to learn more. Number two, the trial locations are inconvenient.
(02:37):
Geography is a major problem with clinical trials because they
tend to be in specific locations that are often not
convenient to patients. Vicky Carr is our breast cancer survivor
and patient advocate for Susan G. Coleman, who lives outside Washington,
d C. For four years, she's taken a bus trip
every four weeks for a trial that will hopefully prevent
her cancer from returning and spreading. Another example, the multiple
(02:59):
scross a study that Dave Bexfield participated in, required ten
round trip flights from Albuquerque to Houston, including initial treatment
and follow up trips. His cost eventually were covered by
insurance company after a big fight. But not everyone has
the luxury of taking so much time off work. But
before you ride off a possibly life saving study, it's
important to know the terms because some trials will pay
(03:21):
for travel and hotel expenses. Number three, Patients worry about
getting the placebo. A lot of people are afraid of
going through all that trouble of participating in a trial
to only wind up in the group that gets the
sugar pill instead of the drug. But nowadays trials are
designed to be more patient friendly. For instance, there might
be several treatment groups and a single placebo group, so
(03:41):
the chances of receiving the placebo may only be twenty
five to thirty three percent. Crossover designs also allow every
participant to receive the drug at some point during the trial.
Another incentive is the open label extension trial. This is
a special trial that allows participants who complete the main
trial to have guaranteed access to the drug at the
end of it. Also, in the case of cancer trials,
(04:02):
people in either group will get at least the current
standard of care for their condition. No one goes without treatment.
Number four reason Patients also worry about safety. They hear
the word clinical trial and figure that the drug being
tested could really harm them, But by the time it
gets to the stage of being tested on humans, the
researchers have already tested this out on cells grown in
(04:22):
a lab, as well as on animals. These are called
preclinical studies. Clinical trials are done only after preclinical studies
suggest that the treatment is likely to be safe and
will work in people. The research must also be approved
by the u S Food and Drug Administration. The researchers
and doctors we spoke with for this story emphasize the
need to have a wider pool of study subjects. Clinical
(04:44):
trials need both men and women of all races and
ages to be sure that a treatment will work on everyone.
And by the way, you don't have to be sick
to participate in a clinical trial. Lots of them are
looking for healthy volunteers. Next up, staff writer Joe McCormick,
who's also the co host of a podcast you might
(05:04):
have heard of called Stuff to Blow Your Mind, presents
a story from our freelancer Dave Ruse about the strange
and very serious world of the sand mafia. As strange
as it may sound, sand is one of the world's
hottest commodities. The global construction boom has created an insatiable
(05:26):
appetite for sand, the chief ingredient in making concrete. The
problem is that sand isn't as abundant as it used
to be, and when high demand and high value. Meet scarcity,
you open the doors to smuggling. Meet the sand mafia.
In India, illegal sand mining is the country's largest organized
(05:48):
criminal activity. In inland villages, armed sand mafia's steel land
in order to strip its top soil and extract the
layers of valuable sand beneath along the posts. Pirate dredging
vessels siphon sand from the seafloor in broad daylight, with
bribed officials turning a blind eye. The Pilford sand fetches
(06:09):
a good price on the black market, where it is
sold to construction companies building high rises in mega cities
like Mumbai. According to journalist Vince Bisser, who wrote about
sand theft for Wired and The New York Times, people
who resist the mafia are beaten or killed, including police officers.
Filmmaker Dennis Dellastroc witnessed similar tactics in Morocco while shooting
(06:33):
Sand Wars, a documentary about the global sand trade and
its environmental impact. According to Dellastrac, quote, the sand of
mafia in Morocco is the second most powerful criminal organization
in the country. We saw people with shovels taking every
last grain of sand from the beach where a few
years ago you used to have a very thick and
(06:54):
white beach. Now you have this lunar landscape. It's devastating.
Environmental officials estimate that half of Morocco's construction sector is
built with stolen sand. The irony, says Dellastroc, is that
much of the stolen sand is used to build housing
for foreign tourists who are flocking to Morocco precisely because
(07:14):
of its beaches. If both legal and illegal sand mining
persists at its current rate in places like Morocco, India,
and across Asia, there may be few beaches left. The
United Nations Environment Program reported in that quote, sand and
gravel represent the highest volume of raw material used on
(07:35):
Earth after water. Their use greatly exceeds natural renewal rates.
Dellastrac claims that eight of everything built on our planet
is built out of concrete, and concrete uses a whole
lot of sand. It takes thirty thousand tons or more
than twenty seven thousand metric tons of sand to construct
one kilometer of highway. It takes about two hundred tons
(07:58):
or about a hundred and eighty men trick tons to
build the average concrete house. Reports Coastal Care, a nonprofit
foundation dedicated to beach conservation. According to a report from
the International Monetary Fund, the Birj Khalifa Tower in Dubai,
the world's tallest building, required more than a hundred and
twenty one thousand tons or about a hundred and ten
(08:20):
thousand metric tons of concrete and over one point six
million square meters of glass. Another industrial commodity that's a
massive consumer of sand, Dubai represents another of the great
tragic ironies of the global sand trade. This booming desert
outposts surrounded by endless seas of sand dunes, must import
(08:42):
most of its construction sand from Australia. That's because desert
sand is too smooth and fine. The rough angular sand
required to make concrete can only be found in or
near water or an ancient seabed deposits underground. Of course,
Dubai isn't alone in its hunger for concrete. According to
a twenty fourteen UN report on global urbanization, fifty four
(09:04):
percent of the world's population now lives in urban areas,
including twenty eight mega cities, Sprawling urban areas with more
than ten million people. The global sand trade generates seventy
billion dollars a year to mine, dredge, extract, and ship
enough raw material to meet the explosive demand for urban housing.
How long though, until we run out of sand? It
(09:27):
takes twenty thousand years for the natural process of sand
formations as dellastrak. Ocean sand begins its journey high in
the mountains, where erosive forces slowly break rocks into smaller
and smaller pieces that are eventually carried by streams and
rivers into the sea. The ocean floor contains a surprisingly
thin layer of sand. Most large deposits are found on beaches.
(09:51):
The scarcity of natural sand makes beaches and shorelines the
ripest targets for both legal and illegal sand mining. The
environmental impact of large scale sand excavation can be disastrous.
More than two dozen small islands in Indonesia have disappeared
due to runaway erosion caused by offshore dredging operations. In
(10:11):
the United States, a sim x sand mining California's Monterey
Bay is blamed by environmentalists for rapid coastal erosion. John
gillis a retired history professor from Rutger's University and author
of The Human Shore Sea coasts in history, says the
most immediate human victims of sand mining and sand theft
are poor fishing communities in the Third World. Quote as
(10:35):
sand gains value in scarcity and becomes a commodity, you
see what happens. It disrupts not just the biological systems
of these places, but also the social systems, driving people
away from their very tenuous hold on the shore. But
if sand mining is left unchecked, the damage to coastal
ecosystems could start swallowing up beaches closer to home. One
(10:57):
more thing, documentary filmmaker Deleastra says that large scale recycling
of industrial materials, especially glass and concrete, is one way
to curb the appetite for natural sand. In Denmark, attacks
on extracting raw materials has created an incentive for companies
to recycle. In nineteen five, only twelve percent of construction
(11:18):
and demolition waste was recycled. By two thousand four, that
number was finally. This week, staff editor Christopher Hasiotis and
our freelancer Justcelin Shields have a piece for us about
one of the fascinating ways that non human animals lacking
(11:39):
a verbal language communicate with one another. Via poop. Most
of us agree it's nice to have a special, separate
area where everyone can relieve themselves. It's objectively great that,
instead of finding piles of human feces all over the
airport or grocery store, we extend to one another the
curb to see if crapping and mutually agreed upon spaces
(12:03):
so civilized. The very humanness of this act might be
why when a group of animals all use a shared
public toilet where all now, isn't that interesting? But let's
not fool ourselves. Plenty of animal species poop in latrines
or middens, and it's not just us fancy pants primates,
nor even just vertebrates. While the act of defecating in
(12:25):
shared communal dung heaps is common in all manner of mammals,
from molds to otters to elephants, some species of ants,
for instance, make refuse chambers in their own nests. Un
Lest we assume the public toilet is a modern invention,
The oldest animal latrine ever discovered was created two hundred
and forty million years ago by a herd of Dinodontosaurus,
(12:47):
giant herbivorous reptiles that kind of resembled a modern rhino.
This prehistoric pile of pooh was gargantuan, covering an area
of almost ten thousand square feet or nine hundred square meters,
with a poop density of around ninety four tirds per
square meter. And speaking of the modern rhinoceros, the critically
endangered white rhino can tell us a lot about what's
(13:09):
probably going on when animals poop in huge communal piles.
Why because white rhinos are seriously into smelling each other's crap.
But let's back up a step. In the past, researchers
have come up with lots of different reasons why a
population of animals would want to create a communal midden
rather than just go behind the nearest tree or wherever.
(13:30):
Since we humans mostly confine our droppings to a specific
area for sanitary reasons, some biologists have assumed that other
animals might be doing the same. And sure, social insects
like ants and spider mites probably do keep their biological
waste and uneaten food separate from their communal living spaces
with the intention of keeping harmful bacteria at bay. But
(13:52):
many other animals, like the white rhino we're talking about,
will regularly just stroll up to a giant pile of
poop and give it a good, thorough investigatory snuffle. They're
probably not all that worried about germs. So communal latrines
have also been thought to mark borders of territories or
even communicate to predators that this heart is large enough
(14:13):
that lunch isn't going to serve itself to them on
golden platters. But for some species, scientists think the purpose
of communal latrines is for intraspecies communication. Period. Take Courtney
Marnoik for example. She is an ecologist and doctoral student
at the University of Quasulu Natal in South Africa, and
she's the lead author of recent study investigating the role
(14:34):
of dung in white rhino communication. White rhinos use communal
defecation sites to communicate. She tells, how stuff works and
this is the only reason they do this. They can
identify age, sex, territorial state, estra state of the depositor,
and even how long ago they were there. And although
Marnoick didn't test for this in her recent study, she
believes rhinos can recognize specific individuals through fecal scent. One
(14:58):
interesting thing about white rhine no midden making behavior is
that every rhino of every age in the area will
all use the same dung heap, but the only one
allowed to poop right in the very center of the
pile is the resident dominant male. He's also the only
one who kicks his dunge around afterwards, spreading his smell
around the midden, but also carrying the smell of his
(15:19):
own poop with him everywhere he walks. According to Marnock,
lots of other animals, both herbivores and carnivores, used communal
defecation sites for communication, sometimes only to mark territory and
pick up signals from other animals, sometimes just for keeping
track of estrus females, and often both, particularly for herbivores species.
She says, there's this hypothesis that communal defecation sites could
(15:42):
potentially be for parasite avoidance, basically, don't crap where you eat.
She highly doubts that this is the case, though, and
thanks communication is the reason for all species. So next
time you're in a public bathroom, you might want to
look around or take a sniff and see what the
world's telling you. Oh and one more thing, completely unrelated
(16:03):
to Rhino's but fascinating. Nonetheless, since we're talking about animal
bathroom habits here, let's talk about sloths. Though they don't
use shared latrines, they do only poop about once a week.
In fact, it's the only reason they climb out of
the tree. And because it takes up to a month
for a sloth to digest its food, they're always very constipated.
(16:25):
That's why each week, defecating sloths undergo what biologists describe
as an ordeal akin to Chipper. Now, that's our show
for this week. Thank you so much for tuning in.
Further thanks for audio producer Dylan Fagin and our orial
liaison Alison Laddermilk. Subscribe to now Now for more of
(16:48):
the latest science news, and send this links to anything
you'd like to hear his cover. Plus tell me what
you're reading right now. I'm reading Grant Morrison's comic The
Invisibles for the first time. Uh and it's very not
safe for work. It very excellent. You can send us
an email at now Podcast at how stuff works dot com,
and of course, for lots more stories like these, head
on over to our home planet now dot how stuff
(17:11):
works dot com.
Welcome to How Stuff Works Now. I'm your host, Lauren Vogelbaum,
a researcher and writer. Here at How Stuff Works. Every week,
I'm bringing you three stories from our team about the
weird and wondrous advances we've seen in science, technology, and culture.
This week, sand is in such high demand and construction
markets around the world that people are stealing tons of it.
(00:24):
And unrelated, it turns out that white rhinos communicate via
massive communal poop piles. But First, Senior editor Katherine Whitborren
and our freelance writer Alia Hoyt take us behind the
scenes of medical research. Clinical trials make amazing new treatments
possible and safe, but here in the United States, they
struggle to find participants. Here's why and what you can
(00:47):
do to help. Dave Bexfield of Albuquerque, New Mexico, was
diagnosed with multiple sclerosis in two thousand and six. Three
years later, he applied for a clinical trial sponsored by
the National Institutes of Health that involved a stem cell transplant.
Bexfield says the trial saved his life. Within a few
months of completion, in twenty ten, he could walk again
(01:09):
without a cane or a walker. Participation levels in clinical
trials are often very low, even for patients with terminal diseases.
Doctor Julie M. Vos, immediate past president of the American
Society of Clinical Oncology, told us that only about three
percent of adopt patients with cancer participate in clinical trials.
This low rate limits patient access to new interventions that
(01:31):
could treat or even cure their cancer. In fact, analysis
of cancer trials found that a whopping forty of them
were unable to enroll the minimum number of participants. Another
survey showed only thirty five percent of Americans said they
were likely to enroll in a clinical trial. So why
don't more people participate in trials, even if it might
save their lives? Here are some reasons. Number one, they
(01:53):
don't know what's available. People diagnosed with diseases often mistakenly
assumed that their doctor will suggest appropriate clinical trials if
they're out there. Although some physicians are very dialed into
ongoing research, many aren't or simply don't have time to
sit through all the opportunities for their patients. So in
addition to asking your doctor directly about clinical studies, you
can also check a number of online resources that can
(02:14):
help you find them. The National Institute of Health website
lists several databases, including clinical Trials dot gov, which allows
users to search by condition or location. Breast Cancer Trials
dot org is another disease specific option where you can
be matched with an appropriate study. Search for finding clinical
trials to learn more. Number two, the trial locations are inconvenient.
(02:37):
Geography is a major problem with clinical trials because they
tend to be in specific locations that are often not
convenient to patients. Vicky Carr is our breast cancer survivor
and patient advocate for Susan G. Coleman, who lives outside Washington,
d C. For four years, she's taken a bus trip
every four weeks for a trial that will hopefully prevent
her cancer from returning and spreading. Another example, the multiple
(02:59):
scross a study that Dave Bexfield participated in, required ten
round trip flights from Albuquerque to Houston, including initial treatment
and follow up trips. His cost eventually were covered by
insurance company after a big fight. But not everyone has
the luxury of taking so much time off work. But
before you ride off a possibly life saving study, it's
important to know the terms because some trials will pay
(03:21):
for travel and hotel expenses. Number three, Patients worry about
getting the placebo. A lot of people are afraid of
going through all that trouble of participating in a trial
to only wind up in the group that gets the
sugar pill instead of the drug. But nowadays trials are
designed to be more patient friendly. For instance, there might
be several treatment groups and a single placebo group, so
(03:41):
the chances of receiving the placebo may only be twenty
five to thirty three percent. Crossover designs also allow every
participant to receive the drug at some point during the trial.
Another incentive is the open label extension trial. This is
a special trial that allows participants who complete the main
trial to have guaranteed access to the drug at the
end of it. Also, in the case of cancer trials,
(04:02):
people in either group will get at least the current
standard of care for their condition. No one goes without treatment.
Number four reason Patients also worry about safety. They hear
the word clinical trial and figure that the drug being
tested could really harm them, But by the time it
gets to the stage of being tested on humans, the
researchers have already tested this out on cells grown in
(04:22):
a lab, as well as on animals. These are called
preclinical studies. Clinical trials are done only after preclinical studies
suggest that the treatment is likely to be safe and
will work in people. The research must also be approved
by the u S Food and Drug Administration. The researchers
and doctors we spoke with for this story emphasize the
need to have a wider pool of study subjects. Clinical
(04:44):
trials need both men and women of all races and
ages to be sure that a treatment will work on everyone.
And by the way, you don't have to be sick
to participate in a clinical trial. Lots of them are
looking for healthy volunteers. Next up, staff writer Joe McCormick,
who's also the co host of a podcast you might
(05:04):
have heard of called Stuff to Blow Your Mind, presents
a story from our freelancer Dave Ruse about the strange
and very serious world of the sand mafia. As strange
as it may sound, sand is one of the world's
hottest commodities. The global construction boom has created an insatiable
(05:26):
appetite for sand, the chief ingredient in making concrete. The
problem is that sand isn't as abundant as it used
to be, and when high demand and high value. Meet scarcity,
you open the doors to smuggling. Meet the sand mafia.
In India, illegal sand mining is the country's largest organized
(05:48):
criminal activity. In inland villages, armed sand mafia's steel land
in order to strip its top soil and extract the
layers of valuable sand beneath along the posts. Pirate dredging
vessels siphon sand from the seafloor in broad daylight, with
bribed officials turning a blind eye. The Pilford sand fetches
(06:09):
a good price on the black market, where it is
sold to construction companies building high rises in mega cities
like Mumbai. According to journalist Vince Bisser, who wrote about
sand theft for Wired and The New York Times, people
who resist the mafia are beaten or killed, including police officers.
Filmmaker Dennis Dellastroc witnessed similar tactics in Morocco while shooting
(06:33):
Sand Wars, a documentary about the global sand trade and
its environmental impact. According to Dellastrac, quote, the sand of
mafia in Morocco is the second most powerful criminal organization
in the country. We saw people with shovels taking every
last grain of sand from the beach where a few
years ago you used to have a very thick and
(06:54):
white beach. Now you have this lunar landscape. It's devastating.
Environmental officials estimate that half of Morocco's construction sector is
built with stolen sand. The irony, says Dellastroc, is that
much of the stolen sand is used to build housing
for foreign tourists who are flocking to Morocco precisely because
(07:14):
of its beaches. If both legal and illegal sand mining
persists at its current rate in places like Morocco, India,
and across Asia, there may be few beaches left. The
United Nations Environment Program reported in that quote, sand and
gravel represent the highest volume of raw material used on
(07:35):
Earth after water. Their use greatly exceeds natural renewal rates.
Dellastrac claims that eight of everything built on our planet
is built out of concrete, and concrete uses a whole
lot of sand. It takes thirty thousand tons or more
than twenty seven thousand metric tons of sand to construct
one kilometer of highway. It takes about two hundred tons
(07:58):
or about a hundred and eighty men trick tons to
build the average concrete house. Reports Coastal Care, a nonprofit
foundation dedicated to beach conservation. According to a report from
the International Monetary Fund, the Birj Khalifa Tower in Dubai,
the world's tallest building, required more than a hundred and
twenty one thousand tons or about a hundred and ten
(08:20):
thousand metric tons of concrete and over one point six
million square meters of glass. Another industrial commodity that's a
massive consumer of sand, Dubai represents another of the great
tragic ironies of the global sand trade. This booming desert
outposts surrounded by endless seas of sand dunes, must import
(08:42):
most of its construction sand from Australia. That's because desert
sand is too smooth and fine. The rough angular sand
required to make concrete can only be found in or
near water or an ancient seabed deposits underground. Of course,
Dubai isn't alone in its hunger for concrete. According to
a twenty fourteen UN report on global urbanization, fifty four
(09:04):
percent of the world's population now lives in urban areas,
including twenty eight mega cities, Sprawling urban areas with more
than ten million people. The global sand trade generates seventy
billion dollars a year to mine, dredge, extract, and ship
enough raw material to meet the explosive demand for urban housing.
How long though, until we run out of sand? It
(09:27):
takes twenty thousand years for the natural process of sand
formations as dellastrak. Ocean sand begins its journey high in
the mountains, where erosive forces slowly break rocks into smaller
and smaller pieces that are eventually carried by streams and
rivers into the sea. The ocean floor contains a surprisingly
thin layer of sand. Most large deposits are found on beaches.
(09:51):
The scarcity of natural sand makes beaches and shorelines the
ripest targets for both legal and illegal sand mining. The
environmental impact of large scale sand excavation can be disastrous.
More than two dozen small islands in Indonesia have disappeared
due to runaway erosion caused by offshore dredging operations. In
(10:11):
the United States, a sim x sand mining California's Monterey
Bay is blamed by environmentalists for rapid coastal erosion. John
gillis a retired history professor from Rutger's University and author
of The Human Shore Sea coasts in history, says the
most immediate human victims of sand mining and sand theft
are poor fishing communities in the Third World. Quote as
(10:35):
sand gains value in scarcity and becomes a commodity, you
see what happens. It disrupts not just the biological systems
of these places, but also the social systems, driving people
away from their very tenuous hold on the shore. But
if sand mining is left unchecked, the damage to coastal
ecosystems could start swallowing up beaches closer to home. One
(10:57):
more thing, documentary filmmaker Deleastra says that large scale recycling
of industrial materials, especially glass and concrete, is one way
to curb the appetite for natural sand. In Denmark, attacks
on extracting raw materials has created an incentive for companies
to recycle. In nineteen five, only twelve percent of construction
(11:18):
and demolition waste was recycled. By two thousand four, that
number was finally. This week, staff editor Christopher Hasiotis and
our freelancer Justcelin Shields have a piece for us about
one of the fascinating ways that non human animals lacking
(11:39):
a verbal language communicate with one another. Via poop. Most
of us agree it's nice to have a special, separate
area where everyone can relieve themselves. It's objectively great that,
instead of finding piles of human feces all over the
airport or grocery store, we extend to one another the
curb to see if crapping and mutually agreed upon spaces
(12:03):
so civilized. The very humanness of this act might be
why when a group of animals all use a shared
public toilet where all now, isn't that interesting? But let's
not fool ourselves. Plenty of animal species poop in latrines
or middens, and it's not just us fancy pants primates,
nor even just vertebrates. While the act of defecating in
(12:25):
shared communal dung heaps is common in all manner of mammals,
from molds to otters to elephants, some species of ants,
for instance, make refuse chambers in their own nests. Un
Lest we assume the public toilet is a modern invention,
The oldest animal latrine ever discovered was created two hundred
and forty million years ago by a herd of Dinodontosaurus,
(12:47):
giant herbivorous reptiles that kind of resembled a modern rhino.
This prehistoric pile of pooh was gargantuan, covering an area
of almost ten thousand square feet or nine hundred square meters,
with a poop density of around ninety four tirds per
square meter. And speaking of the modern rhinoceros, the critically
endangered white rhino can tell us a lot about what's
(13:09):
probably going on when animals poop in huge communal piles.
Why because white rhinos are seriously into smelling each other's crap.
But let's back up a step. In the past, researchers
have come up with lots of different reasons why a
population of animals would want to create a communal midden
rather than just go behind the nearest tree or wherever.
(13:30):
Since we humans mostly confine our droppings to a specific
area for sanitary reasons, some biologists have assumed that other
animals might be doing the same. And sure, social insects
like ants and spider mites probably do keep their biological
waste and uneaten food separate from their communal living spaces
with the intention of keeping harmful bacteria at bay. But
(13:52):
many other animals, like the white rhino we're talking about,
will regularly just stroll up to a giant pile of
poop and give it a good, thorough investigatory snuffle. They're
probably not all that worried about germs. So communal latrines
have also been thought to mark borders of territories or
even communicate to predators that this heart is large enough
(14:13):
that lunch isn't going to serve itself to them on
golden platters. But for some species, scientists think the purpose
of communal latrines is for intraspecies communication. Period. Take Courtney
Marnoik for example. She is an ecologist and doctoral student
at the University of Quasulu Natal in South Africa, and
she's the lead author of recent study investigating the role
(14:34):
of dung in white rhino communication. White rhinos use communal
defecation sites to communicate. She tells, how stuff works and
this is the only reason they do this. They can
identify age, sex, territorial state, estra state of the depositor,
and even how long ago they were there. And although
Marnoick didn't test for this in her recent study, she
believes rhinos can recognize specific individuals through fecal scent. One
(14:58):
interesting thing about white rhine no midden making behavior is
that every rhino of every age in the area will
all use the same dung heap, but the only one
allowed to poop right in the very center of the
pile is the resident dominant male. He's also the only
one who kicks his dunge around afterwards, spreading his smell
around the midden, but also carrying the smell of his
(15:19):
own poop with him everywhere he walks. According to Marnock,
lots of other animals, both herbivores and carnivores, used communal
defecation sites for communication, sometimes only to mark territory and
pick up signals from other animals, sometimes just for keeping
track of estrus females, and often both, particularly for herbivores species.
She says, there's this hypothesis that communal defecation sites could
(15:42):
potentially be for parasite avoidance, basically, don't crap where you eat.
She highly doubts that this is the case, though, and
thanks communication is the reason for all species. So next
time you're in a public bathroom, you might want to
look around or take a sniff and see what the
world's telling you. Oh and one more thing, completely unrelated
(16:03):
to Rhino's but fascinating. Nonetheless, since we're talking about animal
bathroom habits here, let's talk about sloths. Though they don't
use shared latrines, they do only poop about once a week.
In fact, it's the only reason they climb out of
the tree. And because it takes up to a month
for a sloth to digest its food, they're always very constipated.
(16:25):
That's why each week, defecating sloths undergo what biologists describe
as an ordeal akin to Chipper. Now, that's our show
for this week. Thank you so much for tuning in.
Further thanks for audio producer Dylan Fagin and our orial
liaison Alison Laddermilk. Subscribe to now Now for more of
(16:48):
the latest science news, and send this links to anything
you'd like to hear his cover. Plus tell me what
you're reading right now. I'm reading Grant Morrison's comic The
Invisibles for the first time. Uh and it's very not
safe for work. It very excellent. You can send us
an email at now Podcast at how stuff works dot com,
and of course, for lots more stories like these, head
on over to our home planet now dot how stuff
(17:11):
works dot com.
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