Animals of the Nicoya Peninsula, Costa Rica
The Leatherback sea turtle is the biggest of all turtles alive, generally attaining weights of 650 to
1,200 lbs (295-545 kg) and lengths of 6 to 8 feet (1.8 - 2.4 m).
They lack the typical bony shell which other turtles have, instead, they have a leathery shell. The diet of this giant turtle is almost exclusively jellyfish. Leatherbacks are a highly migratory, deep water species. They have a streamlined body and their high fat content provides insulation for dives of up to an estimated 4,265 feet.
Leatherback Sea Turtles are a very ancient species who cruised the oceans at the times of the Dinosaurs, more than a 100 million years ago. Today they top the list of animals in danger of extinction. An estimated 2,500 females are left in the Pacific while in 1980 their number was around 91,000. Development of beaches destroys the particular kind of habitat that leatherbacks need to nest. Humans can crush nests or females are disturbed out of curiosity when they come ashore to nest. In the ocean many die each year from swallowing discarded plastic bags. The biggest culprit however are commercial fishing vessels, who use lines, nets, ropes, and cables that entangle turtles and cause them to drown.
In Costa Rica, one of the most important nesting sites is on Playa Grande, Tamarindo.
The Olive Ridley is the smallest of the sea turtles, usually less than 100 lbs (45 kg) and named for the olive color of its heart-shaped shell. These animals are found in the Pacific and Indian Oceans, along the Atlantic coast of West Africa and the Atlantic coast of South America. This is an omnivorous turtle, foraging offshore in surface waters or dives to depths of at least 150 meters (500 feet) for bottom dwelling shrimp, crabs, mollusks and other small animals. Pollution in the oceans poses a threat to the species, as Olive Ridleys sometimes ingest trash, such as plastic debris and Styrofoam, by mistake.
The Olive Ridley turtle is most noted for its massive nesting aggregations, known as arribadas with literally thousands of females nesting in large simultaneous waves over small stretches of beach. The most important nesting site is in Gahirmatha Orissa, India, other important beaches for mass nestings are in Nancite and Ostional, Costa Rica, and La Escobilla, Mexico. The olive ridley is widely regarded as the most abundant sea turtle in the world but has experienced population loss due to egg poaching, hunting and commercial fishing.