There are a variety of different kinds of snakes in the world, some of which are poisonous and some of which are harmless. Except in a few cases, telling the difference is difficult based solely on looks. Many of the different kinds of snakes are included in the families of Viperidae, Elapidae, Colubridae and Hydrophidae.
The kinds of snakes known as Viperidae, or what many of us know as vipers, are found all over the world. The only areas of the world in which these kinds of snakes have not been found are Australia and Madagascar. These venomous snakes have long, hinged fangs, which allow the snake to enact a deep bite into its victim. Some Viperidae include rattlesnakes, bushmasters, adders, copperheads, and vipers. The bite from one of these snakes can cause any number of problems for the victim, including blood loss, necrosis, swelling, and even disruption of normal blood clotting.
Other kinds of snakes include those in the family Elapidae, which are found primarily in tropical and subtropical areas of the world. These poisonous snakes have fixed, hollow fangs, which can inject venom into the victim. These snakes can be quite small or very large. Some have been found to be only 7 inches (18 cm) long, while others can be as much as 19 feet (about 6 m) long. Most, however, average about 6.5 feet (2 m) in length. Some Elapidae varieties include king cobras, cobras, Australian copperheads, coral snakes, and kraits. The bite from one of these snakes is more dangerous than that from a viper snake and can be toxic.
Found nearly everywhere, the Colubridae snake family includes almost two-thirds of the snake species in the world. These snakes are most often harmless and not poisonous, but some have delivered bites so dangerous the human victim has died. Some of these kinds of snakes include the king snake, corn snake, rat snake, garter snake, queen snake, common keelback, and milk snake.
The Hydrophidae snake family is just as the name implies, as these snakes include many species that live in the water. This group of water snakes is related to the cobra, but they do not live on land like a cobra. Hydrophidae snakes are extremely dangerous, as almost all of them are venomous to humans, with venom generally more toxic than that of land snakes. However, they generally do not bite humans unless they are provoked.