Are Penguins Birds or Something Else?

Penguins are unique animals that challenge our understanding. There are between 17 and 20 species of penguins, also known as Sphenisciformes, with the precise number up for debate among taxonomists. All penguins have a few common traits that help to define them. First, all penguins are aquatic, meaning they live on or near water. Second, all penguins have wings but cannot fly. Finally, all penguins are native to the Southern Hemisphere, with the exception of Galápagos penguins, which live along the equator. This article explores whether penguins are birds and why some of their traits can be cause for confusion.

Are Penguins Birds?

Although penguins cannot fly, they are in fact birds. Penguins are among the more than 60 extant species of flightless birds. Alongside penguins, this list also includes all ratite birds such as ostriches and emus. Let’s discover why penguins are birds rather than mammals.

Why Are Penguins Birds and Not Mammals?

There are two key reasons why penguins are not mammals. First, penguins have feathers rather than fur. This can be confusing because from a distance penguins can appear to have fur. Penguin chicks appear fluffy while adult penguins appear sleek. However, penguins have feathers, not fur. Their unique feathers are shorter and stiffer than other birds, which helps them swim faster and provides insulation in cold climates.

Another reason penguins are birds is that they lay eggs. While there are five extant species of mammals that lay eggs, the remaining 6,490 species have live births. On the other hand, all bird species lay eggs. In fact, laying eggs is one of the qualities that makes a bird a bird.

What Makes a Bird a Bird?

There are three characteristics that distinguish birds from other categories of animals such as mammals, reptiles, or amphibians. Birds lay eggs, have feathers, and have hollow bones. However, birds also have two important qualities in common with mammals: they are vertebrates and warm-blooded.

How Are Penguins Classified?

Penguins are birds, which means they are in the class Aves. Additionally, penguins are in the order Sphenisciformes and the family Spheniscidae. All species in the family Spheniscidae are penguins.

The photo featured at the top of this post is © Michel VIARD/ via Getty Images