Nesting Season, October 1st till the end of February!

The Las Baulas National Park on the Pacific coast of Costa Rica, where Mi Casa Hostel Hotel El Manglar is located, is one of the world's few remaining sites of significant leatherback turtle nesting activity. The numbers of these giant, marine reptiles are declining world-wide and they have disappeared completely from many historically important nesting areas. Various human activities including beachside development, poaching of eggs and accidental capture by fishing vessels have driven the species close to extinction. The Las Baulas (Spanish for Leatherback turtle) project in Costa Rica is dedicated to protecting and understanding the population of turtles nesting in the National Park so that the species may be saved.

Leatherback sea turtles are the largest living marine reptiles and live almost their entirelives at sea. The only times that they are on land is when the female turtles lay eggs, and when hatchlings emerge from the nest and make their way to ocean. We estimate that they are sexually mature at about 10 years or age and may to live to be 40 years old. Studying their biology is very difficult due to the nature of their intermittent visits to land, juvenile and male turtles are almost never seen at all. Consequently, most studies and protection efforts have focused on nesting females and hatchlings.

Leatherback turtles are different to other sea turtles in that they have a soft, cartilaginous shell rather than a hard bony one. It is from the appearance of the shell that the "Leatherback" name comes. They have a more streamlined shape and larger flippers than other sea turtles, reflecting their lifestyle.

Nesting

When the female turtles come ashore to nest, they choose beaches which have particular types of conditions.Crawling up the beach is a slow and tiring process. They are generally free from rocks and have a gentle slope. The turtleemerges from the ocean at night, usually close to the high tide and crawls up the beach until she is above the high tide mark. There she selects
a site free from wood, vegetation and other debris and digs a pit for her body. She does this by throwing sand with powerful strokes of her front flippers until her body sits in the hole created.

Then with her rear flippers she delicately excavates a chamber about 70 cm deep for the eggs. The sand must be of the right texture so that the nest cavity doesn't collapse while it is being dug . She alternates with her rear flippers to reach into the hole and scoop out the sand which is then flicked to the side. When the hole has been dug as deep as the flippers will reach, she starts to lay.

During the period when the eggs are being laid, she becomes very unresponsive to her environment and this is typically when biological information is collected. About 70 large, fertile eggs and 40 small infertile eggs are laid, the function of the smaller eggs is not clear. The turtle then gently packs sand into the hole with her rear flippers and disguises the location of the nest by throwing more sand with her front flippers, possibly to hide he location of the nest from predators of the eggs.

With the nesting process complete, she returns to the ocean about 2 hours after she first emerged and takes no further part in care of the eggs or hatchlings. Female turtles nest on average 7 times in the season, at intervals of about 9 days.

We know very little about the life of leatherback turtles after they leave the beach as hatchlings. They appear to migrate long distances between feeding and nesting areas. Their main diet is jellyfish and leatherbacks have special spiny structures in the oesophagus to trap them there. They have remarkable diving abilities and are able to dive below 1400 metres and to remain submerged for nearly an hour. Useful information is being gained by satellite tracking of adults to try and determine their
 migration routes.