What does a sea turtle mean

Chelonidea Sea turtle

Characteristics

What do sea turtles look like?

Sea turtles belong to the Cheloniidae family. Scientists group them together with the leatherback turtle, which forms a family of its own, in the superfamily Chelonoidea. This includes all turtles that live in the sea.

Sea turtles evolved from land turtles (Testustinidae) around 200 million years ago and differ significantly from them.

Sea turtles have a very typical body: their shell is not hemispherical, but flattened in a streamlined manner.

Depending on the species, it is on average 60 to 140 centimeters long. In addition, it is not completely ossified, so not as hard as that of the tortoises.

Their front and rear legs are transformed into fin-like paddles.

With them, the animals can swim so well that they can travel up to 25 kilometers per hour.

Due to the change in body shape, however, they can no longer retract their heads and limbs completely into their armor in order to protect themselves from enemies.

Where do sea turtles live?

Sea turtles inhabit tropical and subtropical seas around the world, where the water temperature never drops below 20 degrees Celsius.

Sea turtles can only be found in sea water.

They can be found on the high seas, but also near the coast.

Only the females come ashore once a year to lay their eggs there.

What types of sea turtles are there?

There are seven species of sea turtle: the green turtle, the black green turtle, the loggerhead turtle, the hawksbill turtle, the olive and Atlantic hybrid turtle, and the reef turtle.

The smallest sea turtles are the hybrid turtles: their shell is only about 70 centimeters long. The leatherback turtle, the largest of the sea turtles with a length of up to two meters and a weight of up to 700 kilograms, forms a family of its own.

How old do sea turtles get?

Sea turtles are believed to be 75 years old or older.

behavior

How do sea turtles live?

Sea turtles are very good swimmers. The front legs act as paddles that propel them forward, the rear legs act as rudders.

Salt glands on the head ensure that the animals can excrete the salt absorbed with the seawater. This is how they regulate the salt content of their blood.

Sea turtles do not have gills, they have lungs. So you have to keep surfacing to the surface to breathe.

But they have adapted so much to marine life that they can dive for up to five hours without breathing. This is possible because their metabolism slows down so much while diving and their heart only beats very rarely, so that they consume less oxygen.

Sea turtles are vagabonds. They do not stay in a certain marine area, but travel up to 100 kilometers per day. In doing so, they follow the ocean currents.

But they are also based on the earth's magnetic field and perhaps also on sunlight. How exactly this works is not yet known.

The females always swim to the beach where they hatched to lay their eggs, even if they have to travel thousands of kilometers.

The females of a beach arrive at the beach within a few nights, so that all eggs are laid within a few days and the young later hatch at the same time.

Friends and enemies of the sea turtles

The newly hatched baby turtles in particular have many enemies. Often the eggs are looted by nest robbers. Many young people fall prey to hungry birds such as seagulls and ravens on their way from the beach to the sea.

But hungry enemies such as crabs and predatory fish are also waiting in the sea. On average, only one turtle in 1000 reaches the reproductive age of 20 to 30 years.

Adult sea turtles are at most threatened by sharks or schools of predatory fish - and by humans who hunt them for their meat and shells.

How do sea turtles reproduce?

Sea turtles mate in the ocean. Then the females swim to the beach where they hatched. Under cover of night they crawl onto the beach, dig a 30 to 50 centimeter deep hollow in the sand, lay around 100 eggs in it and shovel the hollow back up. The size and appearance of the eggs are reminiscent of a table tennis ball.

On average, a female lays four clutches. Then it crawls back into the sea.

The eggs must always be laid on land, as the babies developing in the eggs do not have gills, but lungs and have to breathe air. If the eggs were to swim in the water, the little ones would drown.

The sun is responsible for the hatching of the eggs. Depending on the temperature, males or females develop in the eggs: if the temperature is above 29.9 degrees Celsius, females develop. If it is lower, males develop in the eggs.

When the young, weighing just 20 grams, hatch after 45 to 70 days, they crawl over the beach into the sea as quickly as possible.

The moon shows them the way: its light reflects on the surface of the sea, which then shines brightly.

The baby turtles instinctively walk towards this bright surface.

maintenance

What do sea turtles eat?

Young sea turtles feed primarily on octopus, crustaceans, jellyfish and fish.

Adult animals also eat seaweed, algae, and seaweed.