Why it's awesome: The hoatzin is often regarded as one of the world's strangest birds. Hatchlings are born with clawed wings ...

For centuries, scientists have observed that animals in warmer climates have longer limbs—a pattern known as Allen's Rule.

From aerial ambushes and vicious territory fights to brutal battles over food and mates, birds can be fierce, feathered warriors. Eagles, owls, hawks, and even tiny songbirds unleash claws ...

This behavior might look playful on the outside, but it means several things in turtle language. Their front claws have other practical uses that aren’t just for swimming, like in this video by ...