Snake (scientific name: Serpentiformes) is a kind of animal under the phylum Chordate and the class Reptile. The body is slender and divided into three parts: head, trunk and tail. There are no limbs or there are claw-like hindlimb remnants on both sides of the transverse cloaca in lower snakes; the body is covered with scales; Ros side, but dorsal in life-long marine snakes (Hydrophidae); protective transparent skin outside eyeball, pupil round, vertical oval or horizontal oval, inactive eyelid, lens almost spherical ; tongue elongated and bifurcated; premaxilla (teeth only in pythons), maxilla, palatine, pterygoid, and dentary attached with retrodented teeth, however size, number, and The structure varies with different snake species; the tail is significantly shorter than the head and body. The habitat of snakes varies from species to species. There are various habitats. Some live in caves, some live on the ground, some live in trees, and some live in water. Snakes are ectothermic animals whose body temperature varies with air temperature, because snakes themselves do not have a well-established thermoregulatory mechanism to generate and maintain a constant body temperature. Snakes are carnivores and eat a wide variety of animals, from invertebrates to various vertebrates. Distributed in all places on earth except the north and south poles.