There are 725 species of poisonous snakes on Earth.
Snakes evolved from a four-legged reptile some 100 million years ago, presumably from a small, wrinkled, landed lizard. Some snakes, like pythons and bulls, still have footprints in the back.
Black Mamba is the fastest of the snakes living on land. It is also the second most poisonous snake in the world. A person's walking speed reaches 5 kilometers per hour. The normal speed of a running person is 15 kilometers per hour. The speed of the black mamba exceeds 20 kilometers per hour. When you meet a black mamba, you better run. Because when you decide to attack you, you don't stand a chance.