Snake

Snakes are long, limbless reptiles that belong to the suborder Serpentes. They are cold-blooded animals with bodies covered in overlapping scales. Unlike lizards, many snakes have special joints in their skulls that allow them to swallow prey larger than their own heads. To fit their slender bodies, snakes have their internal organs arranged one in front of the other, and most have only one lung.

Snakes live on every continent except Antarctica and can be found in many places, including oceans where sea snakes swim. There are about thirty families of snakes, with over 4,000 different species. They range in size from the very small Barbados threadsnake, which is about 10 centimeters long, to the huge reticulated python, which can reach nearly 7 meters. Scientists believe snakes evolved from lizards during the Jurassic period, over 140 million years ago.

Most snakes are not dangerous to people and do not have venom. Those that do have venom use it mainly to catch their food, though some venoms can harm humans. Other snakes catch their prey by wrapping around it and squeezing, a process called constriction. Whether venomous or not, snakes play an important role in nature by controlling the populations of rodents and other small animals.

Etymology

The English word snake comes from Old English snaca, which is related to words meaning "to crawl" or "to creep." This idea is also found in other languages, like Swedish, where "snok" means "grass snake." The word serpent comes from French and also means something that creeps.

Taxonomy

See also: List of snake genera

All modern snakes are part of the suborder Serpentes in Linnean taxonomy. They belong to the order Squamata. The two infraorders are Alethinophidia and Scolecophidia. This split is based on morphological features and mitochondrial DNA patterns.

Snakes are limbless reptiles, but they came from lizards. They look similar to some other legless lizards, such as glass snakes (including the slowworm), and amphisbaenians. Scientists study snake fossils to understand their history. The oldest snake fossils are from the Late Cretaceous period, showing snakes have existed for millions of years. Some ancient snakes, like the Madtsoiidae, were much bigger than snakes today.

Snakes probably came from lizards, and some early snakes had hind limbs. Over time, most snakes lost their limbs. Some snakes today, like pythons and boas, still have small, clawed parts called anal spurs where their hind limbs once were. Scientists are still discovering why snakes lost their limbs by looking at their genes and fossils.

Distribution

There are about 3,900 kinds of snakes. They live in many places, from the Arctic Circle in Scandinavia to as far south as Australia. You can find snakes on every continent except Antarctica, and some even live in the sea. They can be found as high as 16,000 feet in the Himalayan Mountains of Asia. Some islands, like Ireland, Iceland, and New Zealand, don’t have snakes, although New Zealand’s northern waters are sometimes visited by the yellow-bellied sea snake and the banded sea krait.

Biology

Snakes are long, legless reptiles that belong to the suborder Serpentes. They are cold-blooded animals covered in overlapping scales. One of the most famous snakes is the now-extinct Titanoboa cerrejonensis, which was about 12.8 meters long. Today, the largest snakes are the reticulated python, measuring around 6.95 meters, and the green anaconda, which can be about 5.21 meters long and is the heaviest. The smallest snake is Leptotyphlops carlae, only about 10.4 centimeters long. Most snakes are much smaller, usually around 1 meter in length.

Snakes have special senses that help them find food and stay safe. Some snakes, like pit vipers (which include rattlesnakes), have special heat-sensing pits on their heads that let them detect warm objects nearby. Snakes also use their forked tongues to pick up smells from the air or water, which they then analyze in a special organ in their mouths to learn about their surroundings. Their hearing is also good, allowing them to feel vibrations in the ground or air. Vision varies among snakes; some can see well, while others only see differences in light and dark, but most can track moving objects.

Behavior and life history

Snakes have special ways to survive and find food. In cold weather, snakes enter a resting state called brumation. During this time, they stay awake but do not move much. They might rest in burrows, under rocks, or in fallen trees.

All snakes eat meat, such as lizards, frogs, birds, and even other snakes. They catch their food by waiting for it to come close. Because they wait a long time between meals, snakes can go long periods without eating. They swallow their food whole because they cannot chew. Smaller snakes eat smaller animals, while larger snakes can eat bigger animals, like deer.

Snakes have special jaws that let them open their mouths very wide to swallow prey larger than their heads. Some snakes use venom to help catch their prey, while others wrap around their prey to hold it tight. After eating, snakes rest to digest their food. Their bodies change temperature to help break down the food, and they can absorb almost everything except for hair or feathers, which they pass as waste.

Snakes move in different ways depending on where they are. On land, they often move by pushing their bodies in waves, which helps them slither forward. In water, they use bigger waves to swim. Some snakes, like sidewinders, move in a looping motion when they are on sandy or muddy ground. Others use a slow, steady push to move forward when there are no objects to help them push against. Some snakes can even glide through the air by spreading their ribs and moving their bodies in waves.

Interactions with humans

Snakes usually stay away from people and won't attack unless they feel scared. Most snakes, especially those that don't have venom, are not dangerous to people. A bite from a snake that doesn't have venom might hurt a little but is usually not a big problem. But bites from snakes with venom can be very serious and sometimes need a doctor.

People in some places, like India, have shows called snake charming. In these shows, a person seems to control a snake with music. Really, the snake just reacts to the movement of the instrument because snakes can't hear music like we do. Some people catch snakes for different reasons, such as taking venom for medicine or letting the snakes go back into the wild.

In many parts of the world, snakes are eaten as food and are thought to be good for health. Some people also keep snakes as pets, especially friendly kinds like ball pythons and corn snakes. These can be fun, easy pets because they don't need much space and don't eat often.

Snakes have been in stories, symbols, and religions for thousands of years. In the past, they were seen as important and powerful. Today, snakes still mean a lot in many cultures, from religious symbols to parts of medical emblems.