- This isn't what you think it is.
(explosion)
I can see my house from here!
(upbeat music)
We have a lot to thank evolution for:
bacteria that help us digest food,
solvent mucous that lets us smell pleasant things,
skin, but we can't help being just a little
resentful of the ways that evolution
has done us earthlings wrong,
animal and human alike.
Sloths have to live a seemingly lazy lifestyle
because their metabolism is so slow.
Yes, a sloth's stomach may be its most, uh,
slothenly feature.
They can take an entire month to digest one meal.
Sloths have a low body temperature,
but if they get too cool,
their gut bacteria will stop working.
That means that even if a sloth
just ate enough food to fill its belly for a month,
it could starve to death if it gets too chilly
because the food would just sit there undigested.
Slugs are hermaphrodites,
meaning they have both male and female
sexual reproductive organs.
In some ways, it's an adaptation that makes life easy.
Everyone can breed with everyone.
But, in the case of banana slugs,
it can get a little weird.
When banana slugs mate, they both
insert their penises into each other,
but when they are done,
sometimes one or both
simultaneously
will chew the other's penis off.
Why?
Excellent question.
Slugs do bite each other as part of their mating ritual,
but this goes beyond kink.
Some researchers think they just get stuck,
or that it's a competitive behavior
to prevent their partner from impregnating other slugs.
And, no, the penis doesn't seem to grow back.
But, good news, everyone!
They can still use their female reproductive organs
and carry on.
- She got so upset, she ran out of the building,
and a street sweeper ran over her foot
and severed her pinky toe.
(laughter)
- Humans do not need their pinky toes.
Without them you could walk, you could run,
you could probably be a prima ballerina.
- I told the driver, I got a toe here buddy.
Step on it!
(laughter)
- In a study published
in the Journal of Bone and Joint Surgery,
160 subjects all put the least amount of pressure
on their pinky toes while walking and standing.
Their big toes withstood three times as much pressure.
However, we do use the metatarsal bone
that connects the pinky toe to our ankle.
Without it, our feet couldn't properly distribute our weight
and we might not be able to stand up right.
- You did all this for a pinky toe?
(laughter)
- Well, it's a valuable appendage.
(screams)
Tyrannosaurus Rex wasn't a dinosaur to be trifled with.
It had four-foot-long jaws filled with serrated teeth,
but almost as if nature were trying
to even the odds for its prey,
T-Rex's arms were so tiny that it couldn't use them
to grab stuff let alone put food in its mouth.
And T-Rex only had two fingers on each hand,
and most dinosaurs had three,
which makes grabbing a lot easier.
Evolution might've slowly been phasing out T-Rex's arms,
relying on the animal's strong jaw
to pick up and tear prey.
Some researchers propose
that if the dinosaur had stuck around
another million years or so, those arms would've
adapted right into oblivion.
(screams)
One little thing,
we're technically uncomfortable
calling any adaptation bad.
The fact that animals developed and kept these traits
implies that the benefits, no matter how invisible
outweigh the costs, no matter how inconvenient,
or yicky.
So, what's your favorite ridiculous
or ridiculously awesome evolutionary adaptation?
Let us know in the comments.
While you're there, hit the Like button
if you enjoyed this video,
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And to learn more, like
how horrifying hyenas birth canals are,
check out our article
10 Worst Adaptations in the Animal Kingdom
at howstuffworks.com.
I'm the one who...
(explosion)
(single tone)