As whales eat in the water and not drown?

As whales eat in the water and not drown?

Meets Maria Hook, teacher of biology online school “Foxford”.

In fact man can also open your mouth under water, but only near the surface; at greater depth it is dangerous due to high pressure. When we swallow, the epiglottis — the thin elastic cartilage — closes the path into the trachea. Therefore, to choke, opening his mouth under water, people can not. This will happen only in case if he tries to breathe. And the loss of self control due to panic or lack of oxygen this is what will happen — reflex.

Man is not adapted to living in water for two reasons. First, the way the digestive and respiratory systems divided he not as good as those same whales. Second, the development of speech required a different structure of the larynx.

On animals, permanently living in water, fishes and cetaceans — evolution worked differently. Cetaceans the special structure of the epiglottis and the arytenoid cartilage has led to the fact that the esophagus and the Airways did not communicate with each other. Therefore, Keith is free to open his mouth under water and not drown.

The same structure of the pharynx is characteristic of all relatives of whales, dolphins and sperm whales, and other aquatic mammals are characterized by the separation of the respiratory and digestive track. Among them, for example, pinnipeds — seals and sea lions.

However least problems with swallowing under water the bony fish (sturgeon, salmon, carp, perch, pike, etc. — in total more than 20 000 species). The structure of their gills allow water with dissolved oxygen to penetrate the Gill covers to the petals of the Gill where gas exchange occurs, and then water the same way removed from the body. With cartilaginous fishes, such as sharks and rays, the gills are the slits of the pharynx, facing the outside in order to breathe. Therefore, they constantly swallow water and throw it through the Gill slits. And if the bone fish can keep your mouth shut, cartilage, even the food in the mouth can not keep have to tear off and swallow a piece as quickly as possible. But if the fish or aquatic mammal no anomalies in the structure of the pharynx, it will never choke.