Find out why your dog wags its tail while sleeping, what it means, and if it’s normal. Learn about this sleep behavior and what to watch for.

Lemurs, lizards, whales — all are famed for their tails in some way. But which animal has the longest tail of all? In proportion to their bodies, grass lizards have the longest tails of any known ...

Much like a facial expression, a dog wagging its tail can be a clue to a wide range of emotions. Though the popular imagination places dog-wagging squarely in the camp of happy emotions, the behavior ...

The glass door is closed, but Minnie is already vibrating. That’s the only way to describe the opening seconds of this video ...

From iguanas to ancient dinosaurs, discover the surprising ways animals have evolved to use their tails as defense mechanisms against predators.

The question in the title is simple and straightforward, and many people—researchers and non-researchers including dog lovers—all have opinions on the matter. Everyone seems to know why dogs wag their ...

WASHINGTON — Our very ancient animal ancestors had tails. Why don’t we? Somewhere around 20 million or 25 million years ago, when apes diverged from monkeys, our branch of the tree of life shed tails.