You might be surprised to learn that scientists are still answering that question! 

With new tools like genetic analysis, even centuries-old ideas are challenged. Certain physical traits are common to many raptors, however: keen vision, curved beaks, and sharp talons.

Scientists estimate that raptors can see two to eight times better than humans.

With good eyesight often come big eyes. Indeed, raptors’ eyes are very large compared to the size of their heads. If our eyes were the same size as a raptor’s in proportion to our skulls, we would have eyes as big as oranges!

All birds of prey have strong, curved beaks with sharp edges.

They use their beaks like we might use a knife and fork: to cut food, eat, and feed their young. Though raptor beaks all share certain characteristics, there is some variation in size, shape, and function among different species.

Many different types of birds are hunters, but only raptors use their feet to catch prey.

Powerful feet are also important for self defense, to carry prey, transport branches to nests, perch, and walk. Just as each species’ beak differs slightly according to its diet, so do their legs and feet.