In nature, structure is everything. A cheetah can chase prey at 65 miles an hour partly because it has a long tail for balance.
Snakes use all 400 of their vertebrae to help them slither around, and an owl’s large eye sockets help it to see in the dark.
Vertebrates are grouped into five basic classes—amphibians, mammals, reptiles, fish, and birds. Within each group, skeletons look the same, apart from differences of size. The bones of a toy poodle, for instance, look like those of a wolf, only smaller. But even among unrelated animals, it’s easy to spot similarities between their skeletons.