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Poop kind of stinks, but the stuff inside of poop can tell us a lot about the natural world.

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Poop, well, kinda stinks. And when it’s stuck to the bottom of your shoe, it might not occur to you to be  grateful for the opportunity.

But some researchers happen to like poo.  Or more specifically, the stuff in it. Because it has a lot of stories  to tell about the natural world if you know how to read them. I’m not just talking about  what an animal was munching on.

Poop can tell us about everything  from who an animal’s hanging out with, to how likely it is to have babies. All you have to do is be willing to look  very, very closely at some animal droppings. Poop has some pretty great  advantages when it comes to studying animals in the wild.

Researchers can swoop in and take the sample without needing to get too close to the animal. Basically, it’s a way to  avoid bothering them too much. One way to glean information  from animal poop is by looking at the hormones it contains.

These molecules are used to signal  information throughout the body. For example, glucocorticoid levels shoot  up when animals deal with stressful events like severe weather, being around  predators, or being harassed by people. In a 2017 study, researchers  extracted this hormone from.

Cape Mountain zebra droppings. That let them see how stressed out the  animals were at different times of the year, and under different social  and environmental conditions. For example, in the spring,  before the summer rains, the zebra’s glucocorticoid levels were high.

They were even higher for zebra living  in areas with lower quality grass. The zebra were chronically  stressed out from their poor diets. The same study also looked at the levels of the hormone testosterone in male zebra poop.

In areas with more non-breeding males  than females, the male zebra in herds had higher testosterone levels. Herds have one stallion who  breeds with the mares in the herd, and all the other stallions form  their own “bachelor” groups. So the researchers think the higher  testosterone levels may be related to more inter-male competition.

And that’s not a great thing. See, the scientists noticed that  when testosterone levels were higher, the females’ ability to  produce offspring was lower, although they don’t know why that’s the case yet. Overall, poop hormones came  in useful for understanding why a population of animals might be struggling.

And that gives conservationists  some tools to help them. But poop research goes beyond just hormones. Animals’ guts are alive with  the bacteria that help them digest food -their microbiome.

And exactly which microbes are  kicking around in there can provide a lot of information. To figure out exactly what’s in the poop, researchers often use a  technique called metagenomics. It’s essentially grabbing the genetic  material from lots of different microbes in a sample all at the same time.

In a 2021 study, researchers analyzed  fecal samples from griffon vultures in an effort to figure out how they can digest  rotting carrion without getting sick. And it seems like the vultures  might get by with a little help from some microbial friends. The researchers identified nearly 700 enzymes made by the vultures’ gut microbes.

Those enzymes were found to  break down toxins in their food. We’re talking nasty stuff like  Staphylococcal enterotoxin E or AB5 toxins. In humans, those can cause food  poisoning and lead to the symptoms of cholera and whooping cough.

The researchers then made 15 of those  enzymes in the lab so they could test if they actually do break down the toxins. They put those enzymes on a fancy chip  together with pieces of the proteins from the toxic substances in carrion,  and then monitored the results as the enzymes broke them down. And this approach of looking at   all the bacteria together helped them paint a bigger picture than chasing down  species of bacteria one by one.

Poop can even tell us about the social  structure of the animals that pooped it. In a 2015 study, researchers were able to  sort 48 baboons into two different troops living in different parts of the savanna. They did so by looking at the  type and number of bacteria in each individual’s poop.

But that wasn’t a function  of what they were eating. Instead, it depended on which  baboon was grooming whom. See, baboons who spent more  time grooming each other had more similar gut bacteria.

The researchers suggest that might be  because the animals are transferring bacteria from the groomee to  their mouths when they go to lick their hand in between grooming bouts. Pretty gross, but in fairness,  baboons don’t have sinks. But it does mean that the closer  the individuals are to one another, the more often they interact with each  other and the more often they swap stomach residents, leaving a trail for  the researchers to untangle.

This kind of research is so widespread  that one group of scientists have created a poop database to reference. The database contains the genomes  of more than 1,200 bacteria found in the poop of more than 180  different species from all over the world. The scientists who developed the  database hope it will be used to better understand the ecology of different animals, and to keep an eye on potential  disease-causing microbes.

Poop is a humble resource, but a powerful one, in our efforts to help conserve  animals and their habitats. And it’s all thanks to what they leave behind. Thanks for watching this episode of SciShow, and thanks to this month’s  President of Science, Matthew Brant!

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