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Are Bats Birds? The Surprising Answer!

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single bat hanging from rafters

Even though bats fly like birds, bats are not a type of bird. Bats classify as Mammals because they give birth to live young, produce milk, and have strong jawbones with sharp teeth. Birds, in comparison, classify as Aves because they have feathers, lay eggs, and have beaks with no teeth.

Even though bats are not a type of bird, there are still a lot of similarities between the two species. Understanding both the differences and similarities between bats and birds will give you a better understanding of both.

Keep reading to learn why bats are not a type of bird and some ways that bats have similar characteristics to Aves.

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Why Aren’t Bats Birds?

Bats are not birds because they belong to an entirely different class of animals. Bats classify as a Mammal, whereas birds classify as Aves. The fact that bats and birds belong to different classes means that they are entirely different species, and bats are not birds.

two bats hanging upside down from tree
Image Credit: Salmar, Pixabay

Mammals Versus Aves 

Bats and birds belong to two separate classes. Bats belong to the class Mammal, just like us. Birds belong to the Aves class. Because bats belonged to a different classification, they are not a type of bird. Let’s take a closer look at the differences between Mammals and Aves.

Defining Mammals

Mammals are a type of vertebrate. They are defined by having their own mammary glands, which produce milk in order to feed the live young. Humans classify as Mammals, as do dogs, cats, and apes. Mammals are further distinguished because of their hair, forelimbs, and solid bones.

Defining Aves 

Aves, in contrast, do not have mammary glands and do not give birth to live young. Instead, they lay eggs, have bodies covered in feathers, have hollow bones, and have wings instead of forelimbs. As a result, most Aves fly, though not all—penguins are an example of Aves that do not fly.

Bat Hanging
Image Credit: Pixel-mixer, Pixabay

Mammal vs Ave Comparison Chart

Mammals Aves
Bodies covered with hair Bodies covered with feathers
Births live young Lays eggs
Mammary glands Does not have mammary glands
Forelimbs Has wings
Solid bones Hollow bones
Jawbone Has a beak
Teeth Does not have teeth

Why Aren’t Bats Birds?

Based on the definition of a Mammal, bats classify as Mammals, not Aves. Bats are covered with hair, give birth to live young, and feed their live young with milk produced from their mammary glands. Bats also have a jawbone with sharp teeth and solid bones.

Even though bats can fly, they still have forelimbs, not wings. It’s easier to think of the bat’s wings as webbing that connects the limbs to one another, although no matter what way you think of it, bats technically have forelimbs, not traditional wings.

Due to these characteristics, bats are simply classified as Mammals.

Similarities Between Bats And Birds

Even though bats are not a type of bird, there are a lot of similarities between the two. Most notably, bats can fly like birds, which explains why many people make the mistake of assuming bats are a type of bird. Even so, there are more similarities between the two animals to know.

Bat Night
Image Credit: Morchfoto, pixabay


The most obvious similarity between bats and birds is their ability to fly. Even though bats have forelimbs, they have a winglike structure that allows them to take flight like birds. Additionally, both bats and birds have bodies that are streamlined for flying. This includes their weight and the actual structure of the body.


Bats and birds have very similar diets as well. Birds are primarily insectivores, but some species will eat animals. Similarly, about 70% of bat species are insectivores. The remaining are frugivores. Despite these specifications, most birds and bats eat insects, fruit, and nectar.


Although most birds are awake during the day, some are nocturnal. Owls are the most common type of nocturnal bird. Like owls, bats are nocturnal in that they become most active at night.


The last similarity between birds and bats is that they both are warm-blooded. Warm-blooded means that the animals can regulate their own body temperatures, and all bats and all birds fall into the warm-blooded category.

owl divider 2 Conclusion

Despite their ability to fly, bats are not birds. Bats classify as a type of Mammal, which is defined by their mammary glands and ability to give birth to live young. Birds are a completely different class belonging to the class Aves, which is known for its feathers, eggs, and beaks. Because bats and birds belong to different classes, they are not the same.

Although bats belong to an entirely different class, there are still a lot of similarities between them and birds. These similarities go to show the interconnectedness and similarities of our planet and the animals within it.

Featured Image Credit: Jochemy, Pixabay

About the Author Robert Sparks

Robert’s obsession with all things optical started early in life, when his optician father would bring home prototypes for Robert to play with. Nowadays, Robert is dedicated to helping others find the right optics for their needs. His hobbies include astronomy, astrophysics, and model building. Originally from Newark, NJ, he resides in Santa Fe, New Mexico, where the nighttime skies are filled with glittering stars.