Snakes

The snake has long been maligned, mistrusted, and misunderstood. From the Biblical serpent to Kipling's murderous cobras, these creatures have been feared and hated. Snakes, however, perform a very important service to humans, and have a very interesting history.

For centuries, people believed that snakes were very primitive animals, because they lacked legs. When geologists and paleontologists began to understand the significance of the stratigraphic record, however, they learned that snakes were actually the last major group of reptiles to appear, and they arose from animals with legs.

In some modern snakes, such as members of the Booidea (the pythons and boas), remnants of the pelvic bones can be found. Sometimes, the females of this group will show tiny, external structures which are the evidence of these leg remnants.

Snake fossils are fairly uncommon, due to their fragile skulls not being well-preserved, and the vertebrae by themselves might not be recognized as belonging to a snake. The earliest known snakes in the fossil record are found in the Late Cretaceous Period (140 to 65 million years ago). They most likely arose considerably before that time.

Paleontologists are uncertain as to what group of animals the snakes arose from. Snakes share the characteristic of flexible jaws with varanoid lizards (the extant monitor lizards and Komodo dragons and extinct Mosasaurs). Some paleontologists beleive that snakes developed originally from a group of lizards that were burrowers even though most modern snakes have returned to life above ground, others believe that they arose from an aquatic monitor-type lizard.

Modern snakes are generally subdivided into three groups. The Typhlopoidea are small, worm-like burrowing snakes that live in tropical areas; they are first known from the Eocene Epoch (55 to 36 million years ago). The Booidea also date from the Eocene Epoch, but may contain some forms that originated in the late Cretaceous. The Colubroidea, which comprises all other snakes, do not appear in the fossil record before the Miocene Epoch (22.5 to 5 million years ago).

More about the Order Squamata

Go To Page: 1

Articles in this Topic    Discussions in this Topic