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When you imagine a whale, nipples are probably not in the picture. Like, think about it right now. Where would you even find a nipple on that giant body? But whales are mammals, so they must have some way to get milk to their young. And the truth is, they do have nipples, just hidden away where you might not expect. And whales actually aren't alone here; nipples appear in surprising places on a variety of marine mammals. From sleek cetaceans to rotund manatees, here are some sea creatures with nipples in the last place you'd look.

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So if you had to guess where an animal's nipples are, you might start with what you know. Humans generally have two nipples on their chest, one kind of by each arm. And that's not actually far away from what manatees have going on; they have two nipples with one near each of their pectoral fins, but theirs are a little closer to their fins. Actually, a lot closer - they are in their armpits.

Marine biologists think that manatees are fine with nipples in their armpits despite the drag created by not having them tucked away completely, manatees aren't exactly known to be the fastest animal in the world, so they don't need to be perfectly streamlined. They have slow metabolisms and don't really live that fast-paced lifestyle.

But whales and dolphins are sleeker than that. Evolutionary biologists think that these animals hide their nipples to help with their need for speed. To stay hydrodynamic in their travels, whales and dolphins invert their nipples into mammary slits on their undersides, so there's no way that you would have seen their nipples unless they were, like, currently feeding their young.

But if you wouldn't be able to find them, how does a baby whale or dolphin figure it out? Researchers think that baby dolphins are looking for the mammary slits just like we would, only they know what to look for. For instance, bottlenose dolphins are lighter in color along the mammary slits, which may help the babies find their nipples by creating a kind of landing strip along the dolphin's body.

So that solves the problem of knowing where to go for milk, but the baby still can't get to the nipples when they're hidden inside the mammary slits; they have to coax them out in a process called "bumping." Basically, they follow the light-colored landing strips down the abdomen to the mammary slits and use their forehead to bump up against or massage them until the nipples come out and milk starts to flow.

So a lot of the feeding process is up to the baby to figure out. But having nipples at the bottom of their abdomen gives these animals some agency over their milk flow. They can actually flex their tail to stretch out their mammary glands and get the milk going. When there's extra milk left over, the whales can even bump themselves against the ground to get rid of the excess. So, it can be a good thing to have nipples way down there where the abdomen meets the tail.

Of course, that does mean that they are right next to their genitals and anus. So it's hard to say which is worse: having nipples by your poop hole or in your armpits. Either way, they get the job done, and I think that we will just keep doing it the way that we do it. Thank you very much.

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Whale see you in the next video. Whale. I said, "Whale." [laughs]

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