Why are birds not animal?

Answer 1

Because it's a bird, not a mammal. It's not really a "why" kind of question.

If you mean "What specific features of penguins cause them to be classified as birds rather than mammals", the egg-laying bit is generally a pretty big clue. (There are mammals that lay eggs - the monotremes - but penguins have other bird-like characteristics, like the fact that they don't produce milk, which is really the one absolute requirement for mammals.)

Answer 2

They come from two different lines of reptiles. Soon after they first evolved reptiles split into synapsids and sauropsids. Mammals evolved from the synapsids while dinosaurs and the ancestors of all modern reptiles emerged from the sauropsids. Later on the birds emerged as a branch of the dinosaurs.

Answer 3

Birds are not classified as mammals because they do not meet all the requirements of mammals. To be a mammal, a species must be a vertebrate, give birth to live young, produce milk for their young, have fur or hair, and breath using lungs. Birds only fulfill two of these requirements: vertebrate and lungs.

Answer 4

Birds aren't mammals because mammals give birth to their children live while birds lay eggs!

Answer 5

Bird are not mammals because they have feathers instead of fur, do not feed their young milk, and have a few unique features such as hollow bones that distinguish them a distinct class.

Answer 6

Mammals have mammary glands and feed their young milk. Eagles do not have mammary glands

Answer 7

Birds are animals.

Answer 8

Because they give birth in eggs