Why do sea turtles dive underwater?

Researchers have understood why sea turtles often feed and breed in shallow water or on land, but dive very deep in the ocean. People are watching and studying this reptile.

Scientists have long had a headache with the question of why leatherback was born to explore the depth of icy waters. A person who is provided with all necessary diving equipment such as oxygen tanks, diving suits and regulators can only swim in the surface water of a shallow lagoon. So what is the difference?

The mystery becomes more mysterious. The blood of turtle rich in myoglobin should be ideal for storing oxygen . Sometimes they plunged into the water even for kilometers (about three-quarters of a mile).

Jonathan Houghton and Swansea University colleagues in the UK have conducted experiments to find out why heavy, sluggish marine creatures have such a rare activity. They published the results obtained last Friday on the UK's Experimental Biology.

The researchers installed 13 leatherback turtles with data recorders to record the location, temperature, depth of dive and time. The machine then transmits information to the satellite when the animal comes to the surface.

Green sea turtles return to the sea after hatching on Antonio beach in Guanahacabibes National Park in Pinar del Rio province in western Cuba in January. Researchers have understood why sea turtles often feed and born in shallow water or on land but dive very deep in the ocean.

Of the more than 26,000 deep dives recorded in the North Atlantic, only 95 (less than 0.5%) reached levels greater than 300 meters.

A number of hypotheses have been proposed to explain unusual dives.

Researchers argue that this egg-laying reptile dives deep into the water to evade enemies, while others argue that they simply want to cool their bodies.

The third hypothesis is that sea turtles are hunting in deep waters.

But the results that Houghton obtained rejected all of these theories.

If the turtle is trying to swim to not become a big fish lunch, it will surely swim faster than usual. But the data showed that the turtles never rushed into deep diving.

Moreover, they usually spend hours on the water before diving, perhaps to get more oxygen to increase efficiency.

Houghton said: 'Ignoring the surface is a reckless strategy if you want to escape the enemy, because that's where the enemy can detect the shadows of the turtles'.

If keeping the body temperature is cool, it is not satisfactory because the temperature below 350 meters does not decrease much. So the turtles also have no motivation to dive deeper.

But with the theory of food, the study found that this hypothesis is probably half true. Even if the turtles don't eat the food found at extreme depths, they probably want to find food to store later.

Leatherbacks love to eat jellyfish that live in surface waters. But for months swimming from the tropical breeding area in the Caribbean to cooler waters, they have to rely on jellyfish that live in large corporations at a depth of about 600 meters.

Houghton said sea turtles often dive to search for the group when the sun goes down the mountain, then they return to the water at night to enjoy the party.

This may explain why leatherback turtles often linger in an area for days or even weeks after such a deep dive.