There are various types of pythons, from Reticulated pythons and green anacondas, which are said to have a maximum size of 10 m, to Blind snakes, which are about 10 cm in size. The largest poisonous snake in the world is said to be the King Cobra, which has a total length of 5 m or more. There are many unclear points about the evolutionary origin of snakes, but it is thought that they evolved from a part of the suborder Lizards among the scaled reptiles.
Snakes are associated with "long bodies" followed by "poisons", and in fact, more than 99% of toxic reptiles are snakes.
The staple foods vary depending on the species, such as termites, earthworms, snails, frogs, rats, fish, and birds.
Among the modern fauna, birds are most closely related to the evolutionary lineage, and both belong to the archosaurs. The same archosaurs also include extinct pterosaurs and dinosaurs, the ancestors of birds.
Some large species weigh up to 1 ton, including the heaviest group of modern reptiles. Modern species mainly prey on aquatic organisms such as fish, crustaceans and shellfish, and reptiles and mammals that appear in water areas.
Large Nile crocodile and saltwater crocodile are apex predators and have few natural enemies when grown up, but small Australian crocodile and spectacled caiman can be attacked by other large carnivores (jaguars and snakes).
When sunbathing on land, the mouth is often wide open to regulate body temperature.