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Surround a wild animal with humans, and there are bound to be some changes. Here are five animals that show differences in captivity.

Hosted by: Stefan Chin

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Most zoos and aquariums put tons of work into creating environments that mimic animals' natural habitats as closely as possible. But no matter how hard they try, they can't recreate the wild world perfectly.

For starters, animals in captivity have more interaction with humans. And also, they don't have to work as hard to find enough food, are at less risk of being eaten themselves, and get exposed to different microbes. And all that means that animals in captivity can be a little different than their wild counterparts.

But the ways that they're different can tell us a lot about development and behavior. Even our own! With their stylish spots, bold tail stripes, and bright orange cheeks, maybe it shouldn't be surprising that zebra finches are big-time models.

Oh, well it seems I've got that wrong. They're not fashion models—they're model organisms, which means scientists study them to better understand basic biology and how our bodies work. And, most of the time, these studies occur in labs.

Which is interesting, because it turns out that zebra finches are a bit different in captivity. Like, random as it might sound, their eggs hatch differently. In the wild, all the eggs in a clutch hatch at roughly the same time.

But in captivity, they often hatch days apart: so, they're asynchronous. And that's because the birds actually change up how they incubate their eggs. In both environments, when it's time for a zebra finch to lay eggs, she'll lay one egg a day until the entire brood—usually four or five eggs—has been laid.

In the wild, the parents will usually wait until that's done and start incubating them all at once—which means they all hatch together. But in captivity, the birds start incubating each egg as soon as it's laid. So, they hatch one at a time.

Researchers think this change may occur because captive animals are usually given plenty of food. Plus, that food is like right there, so the parents don't need to spend much time foraging. And with all that free time, they're able to hop on their eggs early and spend more of their day incubating them.

And this might be especially important in captivity because it protects the eggs more. See, zebra finches can kind of be jerks sometimes; they're known to destroy the eggs of other nesting couples if they find them unattended. So, the birds may be a bit wary if there are a lot of other finches nearby.

And captive communities are often more dense than wild ones. Even if nesting couples are kept safely apart from other birds—like in different cages—they still hear lots of other birds nearby. So, they may hop on their eggs to protect against the threat—whether it's real or not.

Also, not only do zebra finches incubate their eggs differently in captivity, they start doing it as soon as they enter into it. In other words, they show behavioral plasticity by adjusting their behavior to their environment. Which is really good to know, since one of the big reasons for studying these birds in labs is to make broader generalizations about animals in the wild, and just animals in general.

And this kind of plasticity might mean that scientists can't necessarily do that. Or, at least, if they want to make extrapolations based on what they observe, they have to be super careful, because the trait they're looking at might be completely dependent on context. Now, if a doll falls in a Sumatran forest, does an orangutan play with it?

If you've watched these apes in zoos, you might assume the answer is yes. They absolutely love new stuff. They can't wait to explore anything and everything.

But most wild orangutans won't touch flags, toys, or other unfamiliar objects. And scientists have a couple ideas about why. One is that captivity is safer and more stable.

When they don't have to worry about predators or finding food, they have more time and energy to explore. But some experts think it has more to do with how orangutans learn. Young orangutans are social learners; so, they learn what to do by watching others.

Literally: monkey see, monkey do. Or, in this case, ape see, ape do. And wild adult orangutans aren't adventurous, because new things can be dangerous.

So their young never learn to investigate. In captivity, though, young orangutans have a different sort of role model: their human keepers. And humans really like to touch things.

So, captive orangutans learn to be curious. What's especially interesting about this is that curiosity is tied to creativity and innovation. Orangutans' general lack of curiosity means wild ones aren't innovative—they come up with new tools and ways of doing things almost completely by accident.

Which, in turn, means they struggle to solve new problems. But captive orangutans are the opposite, and much more… like us. And some scientists think this could help us understand how we developed creativity.

It may be that our creative nature arose after we started living in groups and stumbled our way into some innovative tools—like the stone-tipped spear—because that made life a lot safer. We became free to be curious, much like captive orangutans. It's certainly an idea that's worth exploring—and one that scientists only came up with by seeing how our cousins behave in different environments.

Now, orangutans aren't the only animals who become better problem solvers in captivity. When scientists give hyenas a puzzle box with a snack inside, captive hyenas are way better at getting to their tasty reward. But it's for totally different reasons.

And that can teach us a lot about how their brains are different from ours. See, some scientists think primate brains are big because we live in complex social groups. Basically, we need relatively large brains to be better at navigating all those social interactions that accompany that.

And, even more specifically, we need to be great social learners—like orangutans. Well, much like primates, hyenas live in socially complex groups with competition, cooperation, and hierarchies. So you might think they'd be great social learners, too—and that captive hyenas are better problem solvers because they learn from us.

But that's not what happens. Yes, captive hyenas are less afraid of new objects. But they don't pick that up from humans—it seems to just come from being around things made by us all the time.

In fact, hyenas don't even learn from watching each other. Studies have found that hyenas aren't more likely to get a puzzle box open or open it any faster if they watch another hyena open it first—whether they're captive or wild. And success doesn't seem to have anything to do with how much time or energy they have for exploration, either.

So hyenas have big brains, kind of like primates do, but they don't use them in the same way. Instead, their brain size seems to be more directly related to innovation and the ability to come up with new solutions to problems. See, studies have found that hyenas who try a greater number of strategies are more likely to solve a puzzle.

And captive hyenas try more strategies simply because they're not afraid of the weird, human-built box. Hyena brains are probably wired for improvisation because they're generalist carnivores, and when any meat will do, it could pay to try new things. Plus, their environment can be pretty unpredictable, what with herds moving about and other predators—like us—affecting the availability of prey animals.

So, the more innovative they are, the sooner dinner is served. But not all animals get smarter in captivity. Captive Mexican jays are actually worse at solving puzzle boxes.

They interact with the puzzle just as much, and seem to be just as motivated as wild jays, but they're just not very successful. That means it's not a question of their willingness to explore, like with orangutans, and it's not a question of how many strategies they try, like with hyenas. Instead, researchers think it has to do with vigilance.

Being in a new, unfamiliar environment means that the jays don't know what dangers might be lurking. Normally, these social birds all watch each others' backs and issue a warning if there's a threat. But when researchers tested them with puzzle boxes in captivity, they kept them in pairs.

And one other bird likely isn't enough to provide the same feeling of security. So, even though they were totally safe, and there weren't any threats around, they may have been a bit distracted when they tried to solve the puzzles. Now, all of these examples go to show that studying cognition in animals is hard.

Most studies are done on captive animals, whether they're bred and raised in captivity or caught in the wild, housed for the experiment, and then released. But cognitive ability is dependent on context, environment, and tons of other factors. So when we study animals in captivity, we may not be capturing what their abilities really are.

And even when we can say something about one species's cognition, that may not translate to another species that responds to captivity totally differently. So despite our best efforts, we're probably not getting a complete picture of animal intelligence. Now finally, you might think that having plenty of food, not being stressed by being on the lookout for predators, and having tons of extra time and energy would mean that animals in captivity have super strong immune systems.

After all, those are all things that boost human immune systems. Unfortunately, that doesn't seem to be how it works—at least for some species, like the red knot. The blood of captive red knots tends to have fewer infection-fighting white blood cells than the blood of wild red knots does.

And to make matters worse, those cells are also not as good at killing harmful microbes like staph and yeast. It turns out that, while having all the right resources for your immune system is great, if the body doesn't think having a high-functioning immune system is important, it directs those resources somewhere else! And if an animal isn't exposed to many pathogens—like, say, in the relatively sanitized environment of captivity—then, well, the immune system just isn't that important.

The idea that less threat translates to a worse immune system has been around since at least the 1950s. But now, scientists are applying it to a new field called eco-immunology. Eco-immunology studies the way that evolution, ecology, life-history, and environment impact immune responses.

And these interactions are super important to keep in mind, especially when it comes to releasing animals—like, ones that received human care for an injury or illness, or who were born in captivity with the aim of boosting wild populations. And just to confuse things, captivity doesn't always equal a weaker immune response. Studies have found that some animals can develop stronger immune responses in captivity.

Although, those are usually to the pathogens found in their captive environments, and they often come at the expense of their general immune defenses. Other animals, like the red knot and some other bird species, as well as mammals like dolphins, just have overall weaker immune systems in captivity. And that means, individuals that have spent time in captivity may have a higher risk of illness and dying in the wild.

So rehabilitation centers and other programs that aim to release animals need to be careful about how they prepare their immune systems for wild living. Overall, there's a lot of evidence that suggests that animals in captivity can be different from their wild counterparts, whether they're temporary visitors or long-term residents. But the ways they're different aren't the same for all species.

That ultimately means that learning more about the effects of captivity on individual species can give scientists a better idea of how research can and can't be generalized. And, it can help us protect animals that we eventually want to release. Thanks for watching this episode of SciShow!

If you really enjoyed the cognition-related examples in this list, you'll probably love our episode on how fish are smarter than you think. And before I go, let me give a quick shout out to all of our patrons on Patreon who help make everything we do here possible! Thank you for being such an awesome group of supporters!

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