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1. BREEDING
Turtles do not possess highly evolved brains; nevertheless, their sense of vision, smell and hearing are extremely developed, and they have remarkable navigational ability. As a result, even though they live scattered throughout the vastness of the ocean, they know the time and place to meet for reproduction. When the time comes, they travel between continents, back to the beaches where they were born, to lay eggs. Researchers still do not know exactly how to explain this amazing sense of orientation. It is known, however, that their cycle of reproduction takes one, two or three years, depending on the species and environmental conditions, particularly the distance between the feeding and breeding grounds.
Mating takes place in the sea, either in deep waters or near the shore. The female chooses one male among several, and courtship starts with a few bites on the neck. Copulation lasts for several hours, and the female may be fertilized by several males. Fertilization is internal and the female may lay eggs up to three or five times, at average intervals of 10/15 days, each time laying an average of 130 eggs.
The female turtles look for a deserted beach to lay their eggs - in Brazil this is from September to March - and generally wait for the night, because the heat of the sand during the day affects the nesting and the darkness protects them from several hazards. When the night comes, the turtles choose a part of the beach which is free from the action of the tide, and with their flippers, excavate a deep round hole, about six feet in diameter. This hole is called a body pit, and is where they are going to settle to start building their nest. They may make several body pits until they choose one to lay eggs. Any noise, or unfamiliar movement may scare them. Researchers often find half moon-like tracks on the sand which indicate that the turtle went back to the sea without laying eggs.
When the body pit is ready, they use their hind flippers to dig another hole for the nest, which is approximately 1.5 feet deep and looks like a bottle buried in the sand, its neck larger towards the bottom. The turtle lays its eggs there; they are round and white, resembling Ping-Pong balls. The eggs are well protected, covered by a mucous-like substance, and by the sand with which the turtle covers the nest. The turtle lays about 130 eggs each time, but TAMAR researchers have found nests with numbers of eggs ranging from only 16 to as many as 240.
After laying the eggs, the mother turtle goes back to the sea. The eggs hatch around 45 or 60 days later and the baby turtles are born. They scrape away the sand with their flippers. The hatchlings help each other until they reach the surface of the nest and scuttle towards the sea.
2. The Adventure of Life
3. Threats