When was the last time you looked inside of a penguin's mouth?! These loveable birds are harboring something quite gruesome inside that looks more like something from a sci-fi or horror film.
But of course, there is a logical explanation - so what exactly is going on inside of a penguin’s mouth?
Penguins’ mouths contain pronounced growths called papillae which look like sharp spines. These spines cover the tongue and base, and roof of the mouth. They’re made from relatively soft keratin - the same structure that makes up human nails and hair - and they aren’t especially sharp!
Papillae are not unique to penguins. In fact, many animals have subtle papillae on their tongues, including humans. A rough tongue helps animals grip food and direct it into their mouth, which is pretty much exactly what penguins use their own papillae for.
Of course, that doesn’t tell the whole story - read on to find out more!
A look inside the open beak of a King Penguin
Penguins’ mouths contain large, distinctive spines called papillae. The word “papillae” simply means ‘small protuberance,’ but in the case of penguins, they’re actually very large.
These papillae coat most of the penguin’s mouth, including the roof and base of the mouth, the sides, and the tongue. Most animals have papillae - including humans.
These rough protuberances contain taste buds and give the tongue its rough surface. Imagine if the tongue was smooth - it’d be difficult to direct food down the mouth.
Penguin with a wide open beak, showing the inside of its mouth with papillae
The distinctive shape of a penguin’s papillae has evolved because of its diet. Like all birds, penguins don’t have teeth as mammals do, but many have protrusions that help them swallow or filter food. For example, ducks have papillae that help them filter food from water and aquatic vegetation.
In the case of penguins and other seabirds that eat mostly fish and other sea creatures, their mouth protrusions are large because fish are so slippery. They use the spines in their tongue and mouth to grip the fish and direct it down towards their throat.
You’ll notice that all the spines face back towards the throat - this enables penguins to grip the fish and prevent it from slipping away.
The more papillae there are and the bigger they are, the more efficiently the penguin can swallow their slippery food.
Gentoo Penguin with an open mouth
The spines inside a penguin’s mouth are called papillae. They may look gruesome and alarming, but they’re structurally similar to the papillae in our own mouths, which give our tongue its rough texture.
Penguins and other seabirds have extra-large papillae that help them grip slippery food items and swallow them whole. Like all birds, penguins don’t have teeth.
These special adaptations make it much easier to eat without teeth, enabling them to grip food and direct it towards their esophagus so they can swallow it whole. The spines also help collect small prey like algae, plankton, and small shrimps.
There’s nothing unusual about a penguin’s mouth. Exaggerated papillae are found in many different animals’ mouths, especially those that strain food from the water, like sea turtles, fish, and some whales.
Chinstrap penguin looks for the fish in water in Antarctica
Like all birds, penguins have a beak with a hard keratin exterior rather than a mouth.
Their mouth is full of spiny growths called papillae which help them grip slippery food items like fish and direct them towards their stomach. Gripping raw fish isn’t easy - a penguin’s mouth makes it harder for the fish to escape!
Penguins, like other birds, also lack teeth, but the jury is out as to why this occurred. One of the most widely accepted hypotheses is that teeth are heavy, and since birds evolved to become efficient at flight, they eventually lost them through evolution.
Another theory is that teeth formation takes a long time, and baby birds have to feed themselves within just days of hatching.
For example, young birds of prey are fed raw meat almost immediately after they hatch to help them grow. If birds had to develop teeth prior to feeding, this growth period would be slower.
By forgoing teeth, young birds accelerate their growth and give themselves a better chance of survival.
Close up of a Gentoo penguin feeding a molting chick with regurgitated food, Falkland Islands
As far as we know, all penguins have spiny mouths and tongues covered in growths called papillae. There are structural variations between their mouths, but they’re fundamentally similar.
Penguins aren’t alone here either - papillae are common among filter feeders and seabirds ranging from flamingos to ducks and geese. And you’ll even find large papillae among other filter feeders like sea turtles and fish.
Penguins are predatory birds that are prone to aggression. They’re certainly capable of biting and stabbing with their beaks, and the wounds can be pretty serious.
Fights between rival penguins can be vicious and bloody, resulting in grave or even fatal wounds. Penguin’s mouths are full of protrusions called papillae, but these aren’t what you need to be worried about - it’s the penguin’s sharp beak that will do the damage.
Emperor Penguin chick biting its sibling
Birds have varying senses of taste which are mostly quite weak. However, in the case of penguins, this sense of taste is even weaker than average, and studies show they all but completely lack a sense of sweetness, bitterness, and umami (meatiness). That leaves them with sour and salty taste buds.
Penguins swallow their prey whole, and their diets are not especially diverse, consisting almost solely of fish and other sea foods. A penguin’s diet probably all tastes the same compared to the varying omnivorous diets of other birds.
However, studies found that rather than this lack of taste buds resulting from a lack of dietary flavors, the receptors for other tastes work poorly in cold temperatures. It seems that evolving to their cold environments also caused penguins to lose their sense of taste.
African Penguin eating fish
A penguin’s mouth is full of spine-like growths called papillae. Papillae are found in many animal’s mouths and have two primary functions:
Penguins don’t possess something unusual or weird in their mouth - their papillae help them eat slippery fish and other sea creatures. They help the penguin grip fish but also help filter out smaller sea creatures like plankton and algae. The algae, plankton, and other soft food items stick to the papillae, which act as a strainer.
By gripping food with the spiney tongue and mouth, penguins can efficiently pull the food back towards their esophagus. There’s nowhere for fish to escape from a penguin’s mouth!
The papillae inside of a penguins mouth, help them grip onto slippery food like fish and other sea creatures
Both Penguins, and birds are the only class of vertebrates not to have any anatomical structure defined as teeth. Of course, lots of other animals don’t have teeth, but with birds, it's categorical: there is not a single bird that has teeth in the mammalian sense.
Birds used to have teeth around 100 million years ago but lost them through evolution. As a result, their beaks serve a better purpose than teeth.
Like all birds, penguins have tongues. Penguin tongues are often large, strong, and covered in spine-like protrusions called papillae. These help them grip their slippery prey and direct them towards their esophagus so they can swallow them whole.
Penguins and other birds don’t have gag reflexes like humans and other mammals, but they’re still capable of regurgitating the contents of their stomachs.
Penguins can dislodge bones and other hard items if they’re choking.
Brighten up your inbox with our exclusive newsletter, enjoyed by thousands of people from around the world.