Bite-sized fun facts about penguins’ mouths

January 20th is usually a suitably chilly day in the northern hemisphere for us to think about those natives of the southern hemisphere – penguins. Although not all penguins live in the Antarctic, and some live in much warmer waters, some species are endangered.

On penguin awareness day, the focus is on protecting their food sources and habitats from the effects of human population growth and global heating.

Surprising penguins

We’re definitely attracted to penguins. They’re in films and cartoons, they’re soft toys and pictures in our homes. They’re so unexpected, somehow.

When we think of penguins as flightless birds, they begin to make a bit more sense. After all, they do have feathers. Another thing they have in common with birds is that they don’t have teeth.

Can you name two other flightless birds?* 

So what’s in a penguin’s mouth?

They have a bill and a tongue, but no teeth.

First of all, penguins have a beak, with a pointy end to help them to grab their food, typically fish.

The other outstanding feature of their mouth is the spikes on their tongues and the rooves of their mouths, that look like stalagmites and stalactites in a cave. These help prevent the fish from slipping back out of their mouth. These spikes are actually similar to the papillae we have on our own tongues, though, thankfully, ours are a lot shorter. Because the penguins’ papillae all point backwards into their throat, the fish can only move in one direction – into the penguins digestive tract.

A penguins’ mouth, therefore, is well designed for eating fish.

No teeth at all then?

Before they hatch, penguins do have something called an egg-tooth. This is a handy addition to their beak that helps them break out through the shell of their egg. Birds have this, so do turtles, crocodiles and even spiders!

Why don’t penguin have teeth?

Given that birds are descended from dinosaurs and dinosaurs had teeth, shouldn’t birds have teeth?

The school of thought is that teeth are too heavy. Bird evolution is all about adaptation to flight, and teeth could interfere with aerodynamic weight distribution.

So where does that leave the penguin who’ll never make it into the sky?

Gracefully swimming through the oceans with hydrodynamic ease.

• External expert link: You can read more about penguins here

*Other flightless birds include: kiwi, cassowary, ostrich, emu, rhea and more.

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