Humans have many wonderful qualities, but we lack something that’s a common feature among most animals with backbones: a tail. Exactly why that is has been something of a mystery. Tails are useful for ...

WASHINGTON (Reuters) - Director James Cameron's "Avatar" movies are populated by a species of outsized blue beings resembling humans, except with tails. So why does our species lack a tail, ...

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 its ...

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Humans have many ...

(CNN) -- Humans have many wonderful qualities, but we lack something that's a common feature among most animals with backbones: a tail. Exactly why that is has been something of a mystery. (CNN) — ...