What Snakes Do Not Have Venom?

Nonvenomous Snakes

• Of the almost 3,000 species of snakes in the world, most are not venomous. These nonvenomous species include constrictors, such as boas and pythons, and colubrids, such as the corn snake. They also include snakes that belong to families that only include one or two species, such as the sunbeam snake and the pipe snake. Even though not all nonvenomous snakes are in the constrictor families, most nonvenomous snakes constrict their prey to kill them.

Venomous Snakes

• Of all the snake species in the world, only about 600 are venomous species. Some venomous snakes have relatively harmless venom, such as the hognose snake, whose bite is similar to a bee sting. Other snakes have highly toxic venom that can affect the central nervous system or cause tissue necrosis in humans, leading to the loss of limbs or death. This venom helps the venomous snakes stun their prey.

Identification

• The largest snakes in the world, including the anaconda, the reticulated python, the Burmese python and the African rock python, are not venomous and can be identified through sheer size. However, some of the world's venomous snakes can grow to be quite large; for example, the king cobra can grow to 18 feet long. Most nonvenomous snakes will have round-shaped heads, while venomous snakes have triangular shaped heads and features. Most venomous snakes have angular eye ridges, giving them the appearance of eyebrows, while nonvenomous snakes have smooth faces. However, some venomous snakes, such as the coral snake, have the same head shape as nonvenomous snakes. Most venomous snakes have narrow, slit-shaped pupils like cats, while nonvenomous snakes have round ones. Venomous snakes have a tiny hole called a sensory pit on the top of the nose. Nonvenomous snakes do not have these pits.

Mimics

• Some species of nonvenomous snakes' natural defense against predators is that they look extremely similar to highly venomous species. An example of this is the milk snake, which has brightly colored yellow, black and red bands. The scarlet king snake is completely harmless, but closely resembles the very dangerous coral snake. Another example of this mimicry is the harmless watersnake, which has a gray, black and brown banded pattern that closely resembles the cottonmouth snake, which is venomous.