Snake
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Snake (reptile), legless animal with a long, flexible body covered with overlapping scales. Snakes are reptiles, a diverse group of animals that also includes lizards, turtles, and crocodiles. Snakes are thought to have evolved from lizards and share many characteristics with this group—particularly the so-called legless lizards, which have tiny, almost imperceptible legs. But unlike most lizards, snakes have thin, forked tongues, and they lack external ears. And while most lizards have movable eyelids that periodically close to protect and lubricate the eyes, a snake’s eyes are always open, protected by immobile, transparent scales.
Like all reptiles, snakes are cold-blooded, or more correctly, ectothermic—that is, they cannot produce their own body heat. Instead, they rely on the sun to heat their bodies and then regulate their temperature with behavior. Because they do not rely on energy from food to generate body heat, snakes can survive on an extremely meager diet. Some wait for months between successive meals, and a few survive by eating a single, large meal just once or twice a year. When they do eat, snakes swallow their prey whole rather than biting off small pieces. Many snakes have specialized jaws that enable them to swallow animals that are far larger than their own heads. Although uncommon, some snakes, such as the African rock python, have been observed eating animals as large as an antelope or a small cow.
Although all snakes have a long, cylindrical body, many species boast unique modifications suited to particular habitats and lifestyles. Burrowing snakes, for example, have muscular, stout bodies and solidly built heads that they use to push through soil. Sea snakes have flattened, paddlelike tails for swimming, and the long, thin shape of many arboreal, or tree-dwelling, snakes provides agility when navigating between branches. Some snakes, including pythons, retain characteristics that reflect their evolution from lizards or from lizardlike ancestors. These snakes have traces of hind limbs called spurs, which are usually more prominent in males than in females.
The smallest snakes are the blind snakes. One member of this group, the Texas slender blind snake, reaches just 13 cm (slightly more than 5 in) in length when full grown and weighs less than 2 g (less than 0.1 oz). The largest snakes are the anaconda and the reticulated python, both of which grow as long as 10 m (about 33 ft) and can weigh up to 250 kg (about 550 lb). Among most species of snakes, females are larger than males.
Scientific classification: Snakes make up the suborder Serpentes in the lizard and snake order, Squamata, in the class Reptilia.
Like all reptiles, snakes are cold-blooded, or more correctly, ectothermic—that is, they cannot produce their own body heat. Instead, they rely on the sun to heat their bodies and then regulate their temperature with behavior. Because they do not rely on energy from food to generate body heat, snakes can survive on an extremely meager diet. Some wait for months between successive meals, and a few survive by eating a single, large meal just once or twice a year. When they do eat, snakes swallow their prey whole rather than biting off small pieces. Many snakes have specialized jaws that enable them to swallow animals that are far larger than their own heads. Although uncommon, some snakes, such as the African rock python, have been observed eating animals as large as an antelope or a small cow.
Although all snakes have a long, cylindrical body, many species boast unique modifications suited to particular habitats and lifestyles. Burrowing snakes, for example, have muscular, stout bodies and solidly built heads that they use to push through soil. Sea snakes have flattened, paddlelike tails for swimming, and the long, thin shape of many arboreal, or tree-dwelling, snakes provides agility when navigating between branches. Some snakes, including pythons, retain characteristics that reflect their evolution from lizards or from lizardlike ancestors. These snakes have traces of hind limbs called spurs, which are usually more prominent in males than in females.
The smallest snakes are the blind snakes. One member of this group, the Texas slender blind snake, reaches just 13 cm (slightly more than 5 in) in length when full grown and weighs less than 2 g (less than 0.1 oz). The largest snakes are the anaconda and the reticulated python, both of which grow as long as 10 m (about 33 ft) and can weigh up to 250 kg (about 550 lb). Among most species of snakes, females are larger than males.
Scientific classification: Snakes make up the suborder Serpentes in the lizard and snake order, Squamata, in the class Reptilia.
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