Thanks to the Monterey Bay Aquarium for partnering with us on this episode of SciShow!

It otter be a fun one. [♪ INTRO]. Animals snuggling up with baby animals that are not related to them is internet gold.

But memes aside, cute critters taking care of young that aren't their own, or alloparenting, is a real thing that has been documented in more than two hundred seventy species. Take Rosa, for example. That isn't her pup she's snuggling.

You see, she's one of the residents at the Monterey Bay Aquarium who helps foster orphaned otters. And as a surrogate otter mom, she not only ensures that orphaned pups get lots of love, she also teaches them how to be an otter, so they can eventually be released back into the wild. Like, Selka here is teaching a youngster how to break open crab shells to get at the tasty meat inside.

Ooo—Looks like they're a quick study! Which is great, because catching and cracking open crabs is an essential otter skill. And this mama is teaching a little one how to dive and find food buried in the sand!

The fact that these otters are so willing to lend a paw and step in as parents might seem surprising, though. Surprising from an evolutionary perspective, that is. After all, adoptive parents are essentially helping someone else's offspring that carry someone else's genes.

And usually, that care is at the adoptive parents' own expense. They have to use up some of their valuable energy and resources. Like, a mama sea otter eats more than a third of her body weight every day in order to have the energy to take care of her pup.

And if she doesn't have enough resources to take care of herself and her offspring, she'll usually abandon her young within the first few weeks after birth. Taking care of a young animal could have other costs, too, like delaying an animal's ability to have young of their own. So… why would they do it?

Well, it turns out, there are a lot of possibilities. For starters, for Rosa and Selka and the other animals at the Aquarium, resources aren't an issue. The Aquarium's humans make sure everyone has plenty of food.

And the otter moms don't need to worry about sharks or orcas or male sea otters, either. Making sure the animals in their care are healthy and well fed is a big part of how rehabilitation programs encourage potential foster parents to follow their natural inclinations to take care of young animals. And sometimes, that ‘natural inclination' may be much stronger, more like a biological urge to parent.

The Aquarium team has observed wild otters adopting lost or orphaned pups. And, there have been cases of female polar bears adopting new litters. In both cases, biologists think that could be because they were physiologically “primed” for motherhood.

These cases all involve female animals that had recently lost their own young. And if that happened while the females were lactating, they may have still had all these hormones swishing around in their bodies telling them to take care of babies. Plus, since polar bears raise their cubs in dens away from other bears, they might not have evolved good kid-recognizing mechanisms.

In fact, that's probably another big reason alloparenting happens —the animals simply don't realize they aren't taking care of their own kids. This might explain why birds like cowbirds and cuckoos can lay their eggs in other birds' nests and successfully pass along their parenting duties to entirely different species! The parent birds don't want to mistakenly reject one of their own, so they're better off just taking care of everyone in their nest.

And in some species, breeding sites are so crowded that it can be hard to tell whose kids are whose, so parents just take care of whichever ones are nearby. There might be some other benefits to doing that, too. It could be that the young are at least sort of related to them —they're their sister's or their cousin's offspring.

In that case, they share some of the same genes. Plus, there's the possibility of a little “you watch my kid,. I'll watch yours.” That seems to be what happens in many species of whales and dolphins.

Young ones can't always keep up with their fast-swimming, deep-diving parents. And frankly, like most parents, sometimes, cetacean mamas just want a break to do something not kid-related. So, it's common for other adults in a social group to take over parenting duties from time to time.

Sometimes, these alloparents even let the babies drink their milk! And that might be because they're related to the actual parents, as social groups tend to contain relatives. But even if they're not, they might reasonably expect that someone else will take care of their kids when they need someone to lend a hand —or, in the event of their untimely demise.

Plus, these temporary caretakers might be learning a thing or two about how to take care of their own offspring. That seems to be another major reason animals adopt. Studies suggest that such parenting practice is especially useful if animals only produce a few litters in their lifetime or if caring for their kids requires a lot of work.

On top of all of that, there's evidence that foster parents get benefits which help them with non-parenting tasks. Like, they might actually become smarter. A 2015 paper published in the journal Animal Behaviour found that female African striped mice who had raised pups were better able to remember their way through a maze, for example.

And it didn't matter if the mice had raised their own or another mouse's pups. That may be because the act of parenting alters mammalian brains, whether or not the parent actually gave birth to the offspring they're taking care of. If all that weren't enough reason for an animal to alloparent, having a kid around can sometimes give individuals a status boost.

For example, male baboons can temporarily boost their social status and gain protection from other aggressive males if they're seen grooming and taking care of young. And barbary macaques will go even further by placing an infant down between themselves and a dominant male to get social status without needing to fight for it. Some scientists think this trick works because high ranking primates parent more offspring.

The idea is these lower-ranking animals are taking advantage of the fact that the more dominant ones don't want to attack what are likely their own kids. Finally, taking care of someone else's baby might increase an animal's chance of having their own someday. For example, it's thought that the act of adoption may make female northern elephant seals more likely to have offspring the next year.

That's because studies suggest lactation and regular nursing help induce ovulation — which, you know, is kind of important in mammalian reproduction. It's really hard to know if a wild seal has ovulated, of course. But females in this species generally avoid and rebuff males if they're not physiologically ready to get pregnant.

And a 1972 study did note that females who nursed a pup to weaning usually copulated before heading off from the breeding site, while ones that didn't weren't seen mating. In the end, depending on the species, alloparenting may have a whole suite of advantages — and not just for the kid. So it's not actually that surprising so many animals step up and take care of other animals' young.

And it's certainly a help for when our species wants to do some rehabilitation of animals, because these furry or feathered foster parents are a real help. Right now, there are lots of species of endangered animals being saved thanks to the hard work of humans and animal foster parents alike. The Monterey Bay Aquarium's Sea Otter Program, for example, which works with the threatened California sea otter, has been in place since 1984, and has helped more than 700 otters!

And let's give a special thanks to Selka and Rosa for showing off their fostering skills. They're doing the Sea Otter Program proud! Through similar efforts, the Monterey Bay Aquarium and its colleagues in the Association of Zoos and Aquariums give lots of orphaned animals another shot at life, while helping their species return to their historic range.

The Aquarium also participates in programs helping the critically endangered African penguin and the endangered. Western snowy plover, for example. And these programs are just one of the many ways the Aquarium is fulfilling its mission to care for the ocean and everything that lives in it.

If you want to learn more, you can head over to montereybayaquarium.org. And if you want to see more sweet otter cuddles, be sure to check out the Aquarium's Instagram, Twitter, and other social media accounts! You'll find links in the description. [♪ OUTRO].