Archive for the ‘tooth’ tag

Teeth and Venom   no comments

Posted at 5:23 pm in Teeth

Usually, if nature undertakes experiments with poisons, it does not stop half-way, but creates something capable of inspiring real horror, as, for example, poisonous snakes whose bite may be fatal for man.

Now, from where does snake venom come? The venom is merely the snake's saliva secreted by somewhat modified salivary glands opening into a groove inside the tooth. The venom is only secreted when the snake bites, pressing against a little sac at the base of the tooth. During the bite all the venom is injected into the wound.

Some snakes proved very ingenious in developing their lethal weapon. Cobras (the rose and zebra type) and other AfriĀ­can snakes perfected their technique of biting and are very good at spitting their venom. Their poisonous fangs differ somewhat from those of their fellow snakes. The groove along which the venom is ejected does not open out at the very tip of the tooth but some distance away from it (evidently to facilitate ejection), widening into a sort of funnel. For this reason, if the bite is not deep, the poison may not reach the wound, but disperses in fine drops over a wide area. As in a shot-gun the strike area is the larger, the greater the distance between the snake and the target.

Snakes are experts at spitting venom and have a range of up to four metres. This range is achieved by combining the pressure in the venom sac with the inertia of movement, achieved by jerking the head forward with the simultaneous ejection of the venom. If the venom gets into the eyes, the mucous membrane of the nose or the mouth of small mammals, they will die. Such a long-range weapon is more efficient than in other poisonous snakes.

Not only snakes have poisonous saliva. In the Pacific, near the Island of Fiji, New Guinea and Samoa there live gastropod (univalve) mollusks with beautiful, cone-like shells as long as 15 centimetres in length. However, one should not touch these cones. The crafty mollusk is sure to bite you with the sharp teeth of its radula. The poison of these creatures, especially that of the larger ones, is fatal to man.

Written by rickweak on January 6th, 2010

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Importance of Teeth   no comments

Posted at 2:29 pm in Teeth

When asked to name the most important organs in the body, few people remember the teeth, but these, nonetheless, perform a very important function. The teeth frequently help to kill the prey, hold it and then break it up for food. This is why wild animals which have lost their teeth are doomed to death. Even man, who learned to make false teeth and is in no way limited as to his choice of food, is not indifferent to the loss of his natural teeth.

Teeth are equally important both to predatory and herbivorous animals. The well-known Indian hunter Jim Corbett describes several instances when the loss of but a single canine tooth made a tiger attack domestic animals and even humans, as he was no longer able to cope with the large hoofed animals on which he usually fed.

Rodents probably give their teeth more work than any other animal. Even the sharpest teeth cast from the hardest metal would be worn down by such work. The only solution is for the teeth to keep growing. In fact, the front teeth of rodents grow continuously and so quickly that if the animal were deprived of hard food and the teeth stopped wearing down, they would grow to an incredible size and incapacitate their owner. The incisors of rats grow three centimetres a month. If they did not wear them down, every tooth would reach 70 to 100 centimetres by old age.

The elephant's expectancy of life depends on the condiĀ­tion of its teeth. In a free state it feeds on vegetable matter some of which may be rather hard and has to be crushed by its powerful molars. An elephant has only two pairs of working teeth: one pair is in the upper jaw, the other in the lower. In addition, each jaw has five pairs of rudimentary teeth. As the teeth wear out, they fall out and new ones grow in their place until the sixth pair, which is the last, has worn out. The elephant's nutrition gradually deteriorates and this results in its death.

Written by rickweak on December 31st, 2009

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