Crocodiles are considered as one of the most ancient reptiles, their first ancestors appeared on the earth about 250 million years ago. They differ in long life expectancy, rather high speed of movement on the ground, considering the sizes of their trunk and pads, and still a peculiar system of digestion for which improvement of work stones are simply necessary for them.
Instruction
1. Crocodiles – the real predators. Generally they eat water birds and fish, but often attack various Amphibia and do not even shun to try the smaller relatives. In addition such large animals as giraffes, buffalo s and even lions sometimes get to a diet of a crocodile.
2. Despite such varied menu, jaws of these reptiles are not intended for chewing. The abundance of sharp teeth only allows to break off the production on smaller parts which are at once swallowed then. At the same time for once the crocodile is capable to absorb such amount of food which will be the fifth part from its weight.
3. The stomach of a crocodile is simply not able to digest such huge pieces of food consisting not only from meat, but also from bones and even, sometimes, from firm armors of animals. And existence in an organism of undigested food throughout a long time can lead to development of bacteria and even the death of a crocodile.
4. To solve this problem, all crocodiles swallow of stones-gastrolity which represent fragments of rocks or minerals. Getting to muscular department of a stomach of a crocodile, they play a role of millstones, helping to fray fibrous and dense food. At the Nile crocodile, for example, the mass of stones in a stomach can reach up to 5 kg. At the same time stones do not do to the stomach any harm, and over time they in general become well ground.
5. Besides the help in digestion of food, stones in a stomach at a crocodile perform one more important function. They move the center of gravity at these reptiles down and forward that gives to crocodiles big stability during swimming. Without stones the crocodile had to work constantly vigorously paws not to turn over a belly up. And it would already hardly allow to approach the planned production so silently. The same function of a gastrolita is performed also at dolphins, seals, whales and walruses.