Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with many more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads with their highly mobile jaws. To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca.
Living snakes are found on every continent except Antarctica, in the Pacific and Indian Oceans, 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. 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 8.7 meters (29 ft) in length. The fossil species Titanoboa cerrejonensis was 15 meters (49 ft) long. Snakes are thought to have evolved from either burrowing or aquatic lizards during the mid-Cretaceous period, and the earliest known fossils date to around 112 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.
Famous quotes containing the word snake:
“People can be as greedy as a snake trying to swallow an elephant.”
“If this creature is a murderer, then so are we all. This snake has killed one British soldier; we have killed many. This is not murder, gentlemen. This is war.”
—Administration in the State of Sout, U.S. public relief program (1935-1943)
“The Gospel of the army is cunning, as of all other human activities. The wisdom of the snake under the meekness of the sheep is what wins out.
The first Commandment isnever let them get anything on you
The second: Graftget privileges others havent gotworm yourself into confidence
The Thirdseem neat and prosperousas if you had money in the bank”
—John Dos Passos (18961970)