Are Penguins Mammals?

Have you ever seen a penguin on TV, in a magazine, or in a zoo and asked yourself – are penguins mammals? This is a pretty common question and the answer is interesting as well. One reason why many people think that penguins are mammals is that penguins spend most of their time on land or in the sea. So, what is the right answer?

The right answer is that penguins are not mammals. Mammals are classified as vertebrate of the class Mammalia that nurse their young with milk and give birth to live animals. Penguins don’t do either as they lay eggs and feed their young with regurgitated food such as fish, krill, and squid. Penguins can be classified as birds because they have wings that they use as flippers when underwater. Penguins also lay eggs and feed their chicks in the same way as many other birds do.

penguin group small
penguin group small

Even then, when people look at penguins, they often think of them as mammals. In this article, we are going to take a look at some common misconceptions that make people ask are penguins mammals?

  • The Upright Stance – Penguins are often thought of as mammals because they can stand upright on two legs. But the reality is that penguins are aquatic birds that are more agile in the water than on land. Also, add to the fact that penguins are flightless birds and their flippers work better to propel them when they are swimming underwater.
  • Penguin Camouflage – Penguins have a distinct shading with a darker back and a lighter front. This helps them in actively camouflaging when swimming in water so that they are invisible to predators both in and out of the water. While many animals display unique camouflage abilities, this does not mean they are mammals.
  • Penguin Groups – Penguins often stand together in groups to conserve heat, safeguard their chicks from predators, and to provide safety from fast blowing winds to other penguins. Many mammals also display similar huddling behavior which can often lead observers to think penguins are mammals.
  • The Swimming Stance – To go into more detail, penguins are flightless birds that spend their time in the water or on land. If you observe the swimming motion of the penguins closely, you will find out that their swimming action resembles the flying motion of birds in the air. Their flippers have evolved to function better underwater or on land when they lie on their bellies and slide themselves on the ice to move forward.
  • Penguin Skin Looks Like Fur – If you look at the skin of penguins, the feathers are so close together that they actually look like fur. While it is true that baby penguins have fur that helps them to keep warm in cold weather, as they get older, the fur molts away and they grow feathers. These feathers help penguins to trap in air and stay buoyant in the water so that they are able to swim faster. The appearance of the feathers might make them look like the fur of mammals, but that is incorrect. The feathers are waterproof and they help to retain the body heat so that the penguins can survive in a cold environment.
  • Penguin Feeding Method – To feed their newborn chicks, penguins store food in their body that they chew and regurgitate into the chick’s beaks. The resulting mixture of fish sometimes looks like milk which penguins simply place into the beak of their chicks.


To sum up, penguins are not mammals even if their looks and behaviors might make them look like mammals. Penguins are more suitable for swimming and their feeding habits also require them to agile swimmers. The streamlined bodies, waterproof feathers, and wings that act like flippers all point towards the fact that penguins are best classified as aquatic birds.

So, what do you think about penguins as flightless, aquatic birds? Feel free to share your questions, queries or thoughts about penguins in the comment section.


Image Credit:

  1. penguin group small by Antarctica Bound / CC BY

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top