Portal:Snakes/Introduction

Living snakes are found on every continent except Antarctica, and on most smaller land masses — exceptions include some large islands, such as Ireland and New Zealand, and many small islands of the Atlantic and central Pacific. Additionally, sea snakes are widespread throughout the Indian and Pacific Oceans. More than 20 families are currently recognized, comprising about 500 genera and about 3,400 species. They range in size from the tiny, 10 cm-long thread snake to the reticulated python of up to 6.95 m in length. The fossil species Titanoboa cerrejonensis was 13 m long. Snakes are thought to have evolved from either burrowing or aquatic lizards, perhaps during the Jurassic period, with the earliest known fossils dating to between 143 and 167 Ma ago. The diversity of modern snakes appeared during the Paleocene period (c 66 to 56 Ma ago). The oldest preserved descriptions of snakes can be found in the Brooklyn Papyrus.

Most species are nonvenomous and those that have venom use it primarily to kill and subdue prey rather than for self-defense. Some possess venom potent enough to cause painful injury or death to humans. Nonvenomous snakes either swallow prey alive or kill by constriction. (See more…)