No, birds are not mammals. Rather, they are avians. Mammals are characterized by their milk glands, hair, vertebrae and their birthing of live young (being viviparous), according to Britannica.

Most mammals wear coats of brown, black, and gray, while parrots flash brilliant reds, reef fish shimmer in electric blue, and chameleons shift between greens and golds. This disparity is not random.

Many mammals have fur the color of brown and black. Why don't they have more exotic colors, like purple and neon pink?

H5N1, an avian flu virus, has killed tens of thousands of marine mammals, and infiltrated American livestock for the first time. Scientists are working quickly to assess how it is evolving and how ...

An uncomfortable truth is that there is another influenza pandemic in humankind’s future. Whether it will be a relative of the lethal avian flu strain currently wreaking havoc in bird populations ...

While most visitors come for the Gateway Arch itself, the park also supports a diverse mix of animals that thrive in its lawns, trees, and riverfront habitat.