[♪ INTRO] In the wild, it’s easy to imagine that every
species is out for itself. But animals of different species form all
sorts of relationships in nature, and some of them are downright friendly. That’s what you call mutualism: a relationship
where both organisms benefit from the arrangement. Kind of like a “You scratch my back, I’ll
scratch yours, because neither of us can scratch our own
backs cuz our arms are wrong.” Such animal partnerships show just how interconnected
the animal kingdom really is. So today, we’re gonna talk about 8 unexpected
but very real animal duos, from hunting partners to grooming buddies, these animals make interspecies friendship
look easy. Coyotes and badgers are both common predators
in much of North America. But rather than fight for food, the two have
been known to work together as hunting partners. You see, badgers generally
hunt ground squirrels underground. They put dead ends in their tunnels, then
scare them into that trap and dig them out. Sounds terrible. They are not friends. Not friends. Coyotes hunt these squirrels above ground by waiting until they venture far enough from
their tunnels to pounce. And because their styles are so different, if these two predators team up,
they can both benefit. When squirrels detect a badger, they often
run above the ground to escape, right to where coyotes are waiting. And when squirrels detect a coyote, they usually
retreat to their tunnels, putting them right where the badger wants them. A 1992 study found that when working together, coyotes captured 34%
more squirrels than working alone. And while it’s harder to count the prey
badgers catch when they’re in the dirt, badgers that work with coyotes spend more
time underground. Biologists’ figure that’s because they’re
hunting more or eating more, and either way, that’s a win for them. Both of these species are pretty smart and
social and live fairly long lives, so it’s not too surprising that they’re
able to form this kind of relationship. But scientists don’t
see these pairings everywhere. They seem to occur more often where there
are more coyotes and badgers, which makes sense, because there are a ton of
them around, they’re bound to run into each other. And that means there’s more opportunity for an
accidental assist to lead to a lasting partnership. They also seem to happen in areas where there’s
a lot of dense, small bushes. These make it harder for
both hunters to succeed solo, so the benefits of teaming up are all that
more appealing. It’s not just predators that
work together though. Prey species can also team up for extra protection. One of the most well-studied mutualisms is
one that occurs between snapping shrimps and gobies, a kind
of small fish. Dozens of species of these animals pair up. The shrimp is really good at digging, so it digs
and maintains a burrow for the both of them. The goby, meanwhile, has better long-distance
eyesight, so it watches out for predators. And in many pairings, the two communicate
through touch. The shrimp taps the goby with its antennae
to let it know that it’s there, and the goby flicks its tail to tell the shrimp
that trouble’s brewing. Some species in this setup are obligate partners, meaning they literally don’t make it if they don’t
have their brother from another mother, or like, I guess brylum from another phylum. Even when the partnership is optional, though, biologists have found that if you take away
a shrimp’s fish buddy, it eats less, presumably because it’s more worried about
being vulnerable while foraging. And in studies, gobies that don’t pair with
shrimps tend to disappear. Without their well-maintained panic room,
they just get eaten. Of course, it’s not always a single shrimp-fish pair: both the shrimps and the gobies will live
with their mates, too, bringing the twosome to a foursome, or even
a fivesome, since the shrimps frequently form thruples
instead of couples. This partnership makes a lot of sense from
an evolutionary perspective. Gobies are generally fond of hiding places, so it seems like they’d dart into a shrimp
burrow on occasion. And the shrimps probably wouldn’t mind that, if having a goby roommate meant knowing when
to duck underground. Then over time, selection favored individuals
that formed partnerships, and the species began to influence each other’s
evolution, or to co-evolve. Some scientists think they’re seeing this
happen in real time. They’ve found species of shrimps and gobies
that are doing their individual jobs together, but without the specific communication system. So basically, it’s the beginning of what
is expected to be a beautiful friendship. Sometimes, though, a burrow isn’t cozy enough. Sometimes what you really need is a turtle
butt. Take it from oceanic crabs. They have been known to make a home on the
butts of sea turtles, specifically, the little area between the
tail and the upper shell. See, the crabs can’t swim very far, so they
live on anything that floats. But they prefer places where they can hide,
which makes turtle butts the obvious choice. It’s a good home, too. The crabs on turtles tend to be big and healthy,
suggesting they get plenty of food. They’re also more likely to be monogamous,
since there’s room for two and only two. And the females are
more likely to be brooding eggs; a clear sign to biologists that
turtle butt is awesome habitat. For awhile, it wasn’t clear what, if anything, the
turtles got out of having these rear-end residents. Scientists used to think that the crabs ate
the turtle’s poop, which would have made this a
strictly one-sided relationship. But studies of the crab’s stomach contents
revealed that they actually feed on barnacles and other
organisms that attach to turtles. Since these can damage the turtle’s shells
and make it harder to swim, the crabs provide a valuable cleaning service. They’re like live-in maids. On your butt. Some rove beetles live in the fur of small
South American mammals, especially rodents. At first, scientists thought these beetles
were parasites, though that would have made them the world’s
only blood-sucking beetles. But back in the 1980s, a pair of biologists
questioned this idea. The mice didn’t seem to care that the beetles
were there, which is weird, because these are not small
beetles. They’re about a centimeter long, on a roughly
fifteen centimeter-long mouse. The beetles could even walk across their faces
and the rodents didn’t do a thing about it. But, when the scientists placed these beetles on
another mouse species, things were totally different. The mice immediately scratched them off and
killed them. A closer look revealed that the beetles don’t
feed on the mammals directly; they eat the fleas and ticks that do. So, they get a nice, cozy place to live and
all the bugs they can eat. And it turns out the beetles only attach to
the mammals’ fur at night when they’re active. During the day, they just hang out in the
nest. That is most likely how this mutualism started; the beetles stumbled upon the feast of parasites
in the mammal’s nest and decided to stick around. At some point, they got so friendly with their
furry roommates that they started hitching rides, that way, they wouldn’t miss a meal if the
animal decided to spend the day somewhere else. Some small mammals have several nests; others
don’t have a formal nest, and just curl up wherever they see fit. So sticking with the source of their meal
is kind of important. And intriguingly, this beetle-mammal pairing
seems to happen on other continents, too. There are a couple of species of rove beetles
in Australia that sometimes hang out on rats and possums
there. So far, we’ve mostly covered partnerships
between species that wouldn’t otherwise bother each other. But predators and their prey can team up,
too. Look no further than frogs and tarantulas. Large spiders are opportunistic hunters that
often eat frogs, but several species have learned to shack
up with their potential food. These spiders let the frogs live in their
burrows undisturbed, even though they still eat other frogs; they’re
somehow able to tell frog species apart. And scientists think this recognition is chemical. You see, when spiders grab a potential meal,
first they ‘taste’ it with chemical sensors. And researchers have actually taken the skin
from a spider’s partner frog species and glued it onto another frog that the spiders
usually eat. Lo and behold, when a spider grabs a frog
wearing one of these skins, it lets it go, like, “You have no quarrel with me, little frog.
You are wearing the skin of my friend.” The frogs clearly benefit from this partnership,
because, like, they’re not eaten by the spider, and they
get a safe place to hang out. In return, scientists think the frogs eat
ants and other tiny insects that would otherwise attack the spiders’
eggs. It’s not entirely clear how these particular
frogs got so lucky, but the species involved may be generally
toxic or otherwise unpalatable to the spiders. So it’s possible that spiders don’t really
want to eat them in the first place, though how they learned to just let them chill
in their burrow is still a mystery. Speaking of tiny bugs that like to eat eggs:
mites are usually considered pests. But if you’re laying eggs in a popular egg-laying
area, it’s good to have them on your side. Which is why some carrion beetles have struck
a deal with them. As their name implies, carrion beetles eat
dead things, and they lay their eggs in them, too. Well, them and every other fly and beetle
in the vicinity. So, to get a leg up on the competition, the
carrion beetles let the mites ride around on them. The mites eat up all the other eggs and larvae
they can find, leaving the beetles with the perfect nursery
for their eggs. In return, the mites get a free ride to food
supplies they couldn’t otherwise reach. It’s so beneficial for the beetles and the mites
alike that it has turned into a lifelong partnership. The mites reproduce in the same brood chamber
as the beetles, so the mite babies can attach to the beetle
babies from day one. But it’s a delicate partnership. You see, if there are too many mites, they
tend to start eating the beetles’ eggs, too, reducing the brood’s chance of survival. Too few mites or no mites at all doesn’t
immediately harm the beetles, so you’d think that they’d err on the
side of caution. But without the mites, other critters, like,
little worms called nematodes, reproduce unchecked, and the beetles end up carrying them along
with them to each brood site. Those not-so-nice hitchhikers can harm the
beetles’ young, either directly or by competing with them. So, without mites, every subsequent brood
is a little less successful, fewer survive, and those that do are smaller. So ultimately, it’s in both the mites’
and the beetles best interest to team up. Sunfish are the world’s heaviest bony fish,
but they also have another claim to fame: they’ve been known to host more than 40
different parasite species. No one likes having parasites, but in the
open ocean, there aren’t any, like, cleaner fish stations
to stop at. So, these oceanic travelers head to the surface
and follow flocks of seabirds instead. Birds have no problem lending a beak, since
they get a snack in the process. But it’s not exactly easy for them to spot a fish
that’s underwater, even one as big as a sunfish. So the sunfish angle their huge bodies sideways
at the surface and just sit there, patiently waiting for the birds to pluck off
worms or other parasites clinging to their skin. People used to think that this cleaning behavior
happened by accident. Sunfish spend a lot of time in deep, cold
water, so they thought this surface behavior was
just them, like, basking in the sun to warm up. But scientists have found this idea questionable,
since there’s no relationship between how long the fish spend in cold water and
how long they spend basking. It makes a lot more sense if the basking is
for parasite removal specifically. These worms can cause serious damage, so it’s
in the sunfish’s best interest to get them off. Perhaps the cutest pairing in the animal kingdom is the one between common warthogs and banded
mongooses. Not meerkat. Mongoose.
It’s not quite Timon & Pumbaa. We got real close, but it’s not. See, mongooses clean ticks and parasites off
of the warthogs. If a group of warthogs runs into a band of
mongooses, they signal their interest in spa services
by lying down. Then, the mongooses approach and give them
a full body anti-parasite treatment. The warthogs get clean, the mongooses get
a snack. And as the 2016 article in Suiform Soundings
describing the behavior notes, it’s only one of a few known cases of a
mammal cleaning another mammal species. And one other thing that stands out: it only
seems to happen in areas with a good number of people, too, which might
explain how the friendship formed. You see, something similar happens with coatis, a small South American raccoon relative that
looks surprisingly like a mongoose, and tapirs, an animal that is not all that
different from a warthog. Both mongooses and coatis spend a lot of time
around human settlements scrounging for food. And since garbage dumps are popular areas
for wildlife, these animals end up spending a lot of time
around other species. Biologists think that they spent so much time
eating next to other species, that eventually they got comfortable enough
to start picking food right off of them. As these 8 partnerships show, not every species
is out only for themselves. Whether it’s for food, protection, or a
little healthy grooming, a lot of animals have figured out that life can be a little
bit easier when you have a little help. After all, when you’re trying to survive
in the wild, you need every friend you can get. Thanks for watching this episode of SciShow! If you think these animal friendships are
pretty neat, you’ll probably love our episode on symbiotic
bacteria. And to stay up to date with all of our episodes,
be sure click on that subscribe button! [♪ OUTRO]
