American Anole (Anolis carolinensis)

© Zack Bittner

Meet the Ancient Squamates

Squamates have been on Earth for about 200 million years. The ancient animals were small, and we don't have many fossils--but those we have hold clues about how the animals looked and behaved. Scientists think the earliest members of the group had well-developed visual systems for locating moving prey.

If you compare the skeletons of living squamates with those that are extinct, you can see that they're similar. This means that these animals are a great evolutionary success story. Their basic "blueprint" has survived 200 million years of environmental change.

Veiled Chameleon (Chamaeleo calyptratus) catching an insect

© Stephen Dalton / NHPA

The Eyes Do the Walking

Their eyes take in what's ahead, behind, above and below--at the same time!--because they swivel independently. What's more, some scientists think chameleons can accurately judge distances with one eye, something other organisms can do only with two. With such amazing vision, a chameleon that shoots its sticky tongue at an insect, at speeds of up to 5 meters (16 feet) a second--almost never misses.