This is my page dedicated to one of the more unpopular members of the animal kingdom, the snake.
There are a lot of people who don't like them very much but I think they're cool!!
I've had an albino cornsnake of my own for the past four years and she's gotten very pretty over the years. Teri has about five different shades of orange on her.
And new: a slightly fuzzy picture of my snake!!
Ain't she cute? :)
There are a lot of really cool facts about snakes and being able to watch Teri has lead me to appreciate the uniqueness of snakes. I once saw Teri dangling motionless over thin air with only about a third of her on the ground. That was impressive!
FIRST...the links
This site has a link to just about EVERYTHING you'd ever want to know about the little serpents and Reptiles magazine is a really good source of info.
ANYWAY, so we can all get on with life, here's the snake page. (Dun dun DUN)
Okay, basic info about the snake:
The ancestors of modern snakes were small creatures that had long sinuous bodies, smaller legs that were not used as much, and hunted based on the reception and analysis of chemical messages rather than eyesight or hearing. The earliest fossils of creatures that demonstrated snake-like characteristics are found in rocks from the Cretaceous period and are approximately 100 million years old. Snake fossils are rare due to the fact that remains are most likely to become fossilized if the remains are deposited in a body of water so the opportunities for fossilization are limited. In addition, snake skeletons consist of little more than ribs, vertebrae, and a skull. The skull is extremely fragile and often crushed by the predators that fed upon the snake.
There are presently two theories being entertained as to how the snake evolved. One is that snakes evolved from lizards that burrowed underground and so lost their legs, meaning that non-burrowing species of snake emerged from their tunnels and conquered the sea, trees, and other areas above ground. The second theory, which has only been accepted with any amount of enthusiasm within the past decade, is that snakes in fact evolved from mosasauroids, creatures to which both moniter lizards like the Komodo dragon and the ancient, and immense, sea-dwelling Mosasaurus from the Mesozoic era.
The first snakes to evolve were boa-like and were most abundant from 65 million years ago, until 35 to 25 million years ago. The fact that boas and pythons are the most primitive snakes around today is evident in that they still retain a pelvic girdle and have spurs in the place of hind legs while other more evolved families do not. More snake speciation occurred after the death of the dinosaurs and snakes became widespread. From about 35 tp 25 million years ago the colubrids, which are less heavy bodied and faster than boas, entered the scene, earlier snake lineages began to die out, and the numbers of boa and python-like species decreased. Between 22.5 to 5.5 million years ago, the colubrids diversified rapidly and into great numbers. Of the 2400 species of snake present today over 1500 species, about 80 percent, of them are colubrids. Around the same time the colubrids were diversifying, the Viperidae and Elapidae families evolved. The Viperidae family is said to be the most evolutionarily evolved family. By the time five million years ago came around, most modern species of snakes were in place.
As they are without legs, snakes developed different methods of locomotion. One method, called serpentine, is the method that is most identified as being used by snakes. In this method the snake uses its strong muscles to push against irregularities in the soil or, in arboreal (tree-dwelling) species, against tree limbs. Serpentine locomotion is also used when snakes swim, only the snake pushes against the water instead of against a solid surface. Concertina locomotion is used by a snake when it is in close quarters. Using this form of locmotion, the snake anchors the back half of the body, pushes the front half of its body forward, anchors its front half, and moves its back half forward. The heavier snakes like boas and pythons use rectilinear locomotion. In this type of movement the ventral scales 'dig into' the soil and the muscles then pull the snake forward so it moves almost in a straight line. All snakes are fast and even though the fastest timed snake was a green mamba at 7mph, any snake when disturbed can move faster than the average human being.
The skeleton of the snake consists of the skull, vertebrae and ribs. The vertebrae are connected by a ball and socket joint which provides for the wide range of movement seen in snakes. To avoid the twisting of the spinal cord which could result from the ball and socket joints, the vertebrae have wing-like extensions on them that loosely interlock with other extensions on the next vertebra. This prevents the snake from turning completely around and damaging the spinal cord while still allowing for a wide range of movement. Pairs of ribs are attached to each vertebrae until the tail at which point there are only vertebrae. The number of pairs of ribs depends on the snake and some snakes have more than 400 pairs. The pelvic girdle in the boas and pythons (mentioned on the evolution page), is located where the rear legs would be found on an animal that had legs. These girdles and the spurs at the end of the vestigal "legs" are evidence that snakes evolved from an animal that had legs.
The skull is the part of the skeleton that changes the most depending on the family to which the snake belongs. Every snake's skull is delicate and has loosely interconnected bones that can be stretched to allow the snake to swallow large prey items whole. The upper and lower jawbones can move backward, forward and outward and can move independently of each other. To further complicate matters, most snakes have two upper jaws which means there are four sections of upper jaw that can move independently in addition to the two sections of the lower jaw.
Not all snakes have teeth in their jaws. African egg eating snakes for example, which eat only eggs, do not have teeth as they are not really needed. Most snakes have teeth that are approximately the same size but poisonous species developed larger teeth through which venom is administered. The rear-fanged species have one or two enlarged pairs of teeth in the back of their mouth, but their venom usually has a low potency and does not pose a danger to humans. In the Elapidae family (cobras, coral snakes etc.), there are two short hollow fangs that are attached to the upper jaw. These snakes are highly poisonous and, in the case of cobras, bite several times and must 'chew' their venom into their victim because their fangs are short and immobile. The snakes in the family Viperidae are perhaps the most famous poisonous snakes because these snakes have developed long, hollow, hinged fangs that are folded up against the top of the mouth when not in use. When the snake bites the fangs are flung out to inject venom into the victim more efficiently.
I got most of my info from the book The Encyclopedia of Snakes by Chris Mattison so if you want to read the book for yourself or just see the neat pictures go for it! Some of the info about snake evolution may not be in that book because I got some of the info from magazine articles when I did a project on snake evolution in the spring of 1999. Sorry but I forget where they came from.
