For thousands of years, millions of monarch butterflies have migrated from the northern U.S. and Canada to Mexico for the winter. But exactly how they know where to go is still a mystery.

Despite the name, these invasive birds are not actually sparrows but weaver finches, related to other weavers in Africa and elsewhere. European Starling Starlings, which are from Europe and Asia, ...

With large goggle-like eyes, webbed feet, and a full-body wingsuit made of skin, the flying lemur looks like an ...