The more salty the sea, the less blood sharks are

The amount of blood in each shark depends on the salinity of the surrounding seawater. Similarly, the volume of other liquids is also regulated by the environment. This is one of the most extensive studies on this phenomenon so far.

Although water is absorbed by gills, sometimes sharks also drink seawater and discharge urine to keep the body in balance with the environment."The adjustment of body fluids is important to them as important to humans , " said lead researcher Gary Anderson, from the University of Manitoba.

The team analyzed previous studies and data on cow sharks, bamboo sharks, some angled fish and other sharks and rays. They found that in conditions of freshwater or light salt, sharks have much higher blood volume than in saltwater.

Shark.(Photo: Discovery)

According to the team, sharks change blood volume and body fluids through at least five different processes:

- First, it sucks water through the gills, but sometimes this is not enough.

- Drink directly. When two angled shark fish are put into a saltwater tank of 80 to 100% concentration, they drink water like the thirsty person is.

- Another way to regulate fluid is to change the amount of urine released.

- In addition to kidneys, sharks also possess a rectal gland, made from specialized tissues for salt storage. It also affects the amount of blood in the body, but the full function is still unclear.

- Finally, the intestine also plays an important role to keep the fluid balanced with the environment. If too salty, intestinal cells will have to work harder to remove excess salt.

Although these complex processes allow sharks to adapt to the natural environment over the centuries, the warming earth can disrupt those processes.

T. An