Environment and behavior
Sea turtles spend all their lives in the water, with the exception of the females who, during the nesting period, come up onto the beach to lay their eggs beyond the high-tide line. Either at night or very early in the morning, they use their rear flippers to dig a nest in the sand. Depending on their size, they can lay anywhere between 70 and 100 eggs, which they then cover up with sand before returning to the water. They may do this up to seven times during a single egg-laying season, but after that, they won't lay eggs again for another two to three years. Although protected by the sand, the eggs can be subject to heavy predation by dogs, insects, and so on. They hatch about 60 days after being laid, depending on the incubation temperature. This often takes play at sunset or during the night. Their emergence from the nest takes 24 to 48 hours, with their collective motion simplifying the process. This laborious movement allows the newborns to develop the muscles in their flippers, giving them a better chance to quickly cross the distance separating them from the ocean. Because during that race to the water, newborns are particularly vulnerable to heavy predation (crabs, stray dogs, birds, etc.). The waves propel the young turtles into the sea, where many other marine predators further reduce their chances of survival. It is estimated that only one newborn in 1,000 will reach sexual maturity.
The eggs and young turtles are the victims of a multitude of predators. The main predators of adult turtles are killer whales and polar bears.
Because turtles are migratory animals, they accumulate a large number of threats: accidental catches in fishing nets, intensive poaching of eggs and adults, development of tourism and commercial fishing infrastructure close to nesting sites, oil and heavy metal pollution, ingestion of plastic bags that they mistake for jellyfish, and the list goes on.