Monday, January 30, 2012

How snakes became what they are now

Snakes are on this planet for millions of years, and perhaps the most suitable of the reptiles. We do not really know much about how they evolved over the years (their skeletons are very fragile, so fossils are limited), but they probably appeared around the time of the dinosaurs and the origin of lizard ancestors of both the monitor lizard . One of the oldest snake skeleton was found in the Sahara desert, and go back to 130 million years ago.

The snake ancestors were probably aquatic environment at first, but then they got the advantage that their eggs can be laid on the ground and thus enable them to survive on land. A process over millions of years caused them to Burrow, and it is enough if they lost their legs and outer ear, making them suitable for burrowing. Their eyes were replaced by a clear standard to protect them while digging. But some biologists believe that this happened while they were still alive in the water, so there is some disagreement.

Millions of years later some of these animals came to the surface, and the snake as we know it today was born. These snakes were Boidae group, pythons and boa today, making it the most primitive snake snakes alive today. Pythons actually still have remnants of their hind legs, called spores that stick out the bottom of their tails. The Boidae has no poison, but uses constriction to kill their prey.

Approximately 40 million years ago, there was little snakes were further developed, adapted to the new areas and created new features, and these tubes were members of colubrid group, which is the largest snake group today. Colubrids are some of the snakes, called "New World" snakes. A member of this family's corn snake!

At first snake in the world was largely dominated by Boidae, the colubrids were unable to take in large pythons and boas. If the world went through a dramatic change, temperatures were cooler, which reduces the number of Boidae. They could not survive in the cooler temperatures, which made it possible for colubrids to spread over large areas, they came to temperature and climate more tolerant than be Boidae.

The Boidae (pythons and boas) is now limited to those parts of the world with high temperatures, whereas colubrids can survive almost anywhere. Not surprisingly, the number of colubrids greatly increased and they spread all over the world.

Over time some of the colubrids developed rear teeth. The rear fanged snakes, their fangs at the back of the mouth to make the poison is not intended that the only weapon against prey, but rather as a means of narrowing the filling. Many people remain behind fanged snakes as pets (eg hognose snake and gardener), because it's rare that you poison injection of the person you would have to get your hand all the way into the mouth of the tube to get the injection.

For one thing clear in the case of misunderstanding, corn snake (and the milk snake and king snake) is NOT behind the teeth. They have no poison at all.

This page is about corn snakes and ball pythons, but I include some information about how snakes evolved further comprise, you can use as reference.

After a few colubrids developed rear teeth, another group created which is named Elapids. I must say mamba to make it clear that this group of snakes use their poison as their main defense and attack. The elapids have short fangs in their upper jaw that can inject poison and fangs are hollow and gets its poison from the poison gland in the cheek of the snake. The elapids inject poison much more effective than the rear fanged snakes. Other members of this group are cobras, sea snakes, Taipan and additions. Their fangs are basically what separates this group from colubrids, otherwise they are very similar.

Snakes evolved even further, a few million years ago, the group began to develop vipers. Their fangs are much longer than elapids. The group gets its name because most of the viper is ovoviviparous, they give birth to live young (no eggs). In Latin "in vivo" = "I live" and "pario" = "I give birth". The rattlesnake, probably the most "advanced" snake alive today evolved from Viper to non-shed skin at the end of his tail that he can use to warn predators.

At the end of the hose story, they evolved from a monitor lizard, went through a phase of burrowing, came to the surface leg and earless, and has grown into different groups, each with its own characteristics. Since the tubes have been here since the dinosaurs, and they are still thriving around the world (except the polar regions), snakes are one of the most flexible and being successful in life.

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