[Cameron] The internet loves honey badgers. And kittens. And tardigrades. But hey koala,
do you know what the internet thinks about you? [Koala] That I’m cute and cuddly, right?
[Cameron] Well… [Koala] What the...
[Cameron] ...well, this is awkward. I'm Cameron and this is MinuteEarth.
It turns out that much of the koala slander on the internet just isn't true. So let's go
through it, and see what science has to say. [Koala] OK so, according to the internet,
I have the tiniest brain of all mammals. On top of that, my tiny brain has no wrinkles,
which means that I apparently “can’t think.” [Cameron] Ouch. There’s a lot to unpack here.
First: We used to think that animals with bigger brains relative to their body size were smarter
than animals with relatively smaller brains, but that’s not exactly how it works out. Plus,
we could spend all day debating what “smarter” means for an animal, anyway. Second, we used to
think koala brains were absurdly small relative to their bodies, but that impression came from a
shriveled brain that had significantly shrunk after being pickled in formaldehyde. Brain
scans on living koalas show that their brains are basically average-sized, at least for a marsupial.
And about those wrinkles, or lack-thereof. We humans are used to looking at primate brains,
which tend to have that walnut-like surface. Scientists think that these wrinkles increase
the brain’s surface area enough to make more connections between more neurons,
which does imply that wrinkle-less brains might be less complex than wrinkly ones.
But birds’ brains are smooth, and some species can make tools and shout swear words. And the
famously-ingenious octopus has a smooth donut for a brain. So wrinkles aren’t everything.
[Koala] It says here that if you pick eucalyptus leaves and lay them out on a plate, I won’t
recognize them as my food, and I will starve. [Cameron] Being unable to recognize your own
food does sound pretty bad. But no koala expert I talked to could confirm this anecdote. Despite
whether they recognize leaves on a plate as food or not, there's actually a good reason
koalas might not want leaves on a plate. See, even the most nutritious eucalyptus leaves are
pretty low in calories and nutrients compared to other food, so koalas are really picky about which
leaves they eat; they generally don’t bother with the older, less nutritious fallen leaves. And
leaves on a plate would probably look and smell a lot like fallen leaves to a koala. So ignoring
those leaves is actually pretty clever. [Koala] OK, well speaking of eucalyptus,
apparently I'm stoned all the
time because eucalyptus leaves are toxic. [Cameron] To be fair, you are pretty lethargic,
and that is totally because of your food. But you are not getting high. Eucalyptus leaves are
toxic to most animals, but not to koalas. That’s because you koalas have super-long
digestive tracts – including a six-foot long caecum – full of specialized gut bacteria that
detoxify the leaves. But all that digestion takes a lot of time and energy – and remember,
the leaves aren’t that nutritious to start with – so you koalas have to be energy efficient…which
does make you act kind of like stoners. Next! [Koala] Apparently, We wear our teeth down
to the point where we can't chew anymore, and then starve and die.
[Cameron] This isn't fair. Many other plant eaters wear their teeth down over time by
near-constant chewing, but they all tend to die before their ground-down teeth become an issue.
But koalas have so few natural predators that many live long enough for chewing to become difficult.
At that point, koalas compensate by regurgitating partially-digested food to chew it again, which,
I assure you, is not your grossest behavior. [Koala] No, it’s not – I once ate my mom’s poop.
The internet also makes fun of us for that. [Cameron] Yeah, that…the technical term is
“fecal pap.” Remember those detoxifying gut bacteria? Baby koalas aren’t born with them;
they have to eat their mother’s feces to colonize their digestive tracts. And
that is gross, but it’s not uniquely gross. Baby elephants do basically the same thing,
but they don’t get the same hate. Same goes for panda babies, which I'm pretty sure the internet
has determined to be the cutest things around. So hey, koala, don’t let the hate get you down.
Sure, you’re sleepy, slow, and a bit weird, but as far as animals go, you’re pretty high-koala-ty.
You’re not a koala, so if you’re struggling from anxiety or depression,
fun science facts alone might not be the best solution. Instead, you may want to
talk to a licensed professional – like a therapist from BetterHelp,
which sponsored this video. BetterHelp is the world’s largest online therapy service,
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betterhelp.com/minuteearth or simply by clicking the link in the description. Thanks, BetterHelp!
I’d like to thank our friend Toby from the channel Tibees for voicing the koala in this
video. If you’re interested in super deep dives into mathematics, astronomy, and the history of
science, make sure to go check out her channel Tibees. She’s doing great stuff over there. Bye!