Sunday, May 16, 2010

Leatherback Turtles at Grande Riviere

Last weekend I went to the NE corner of Trinidad to an area called Grande Riviere to watch the leatherback turtles lay their eggs. This is one of the last things that I felt like I had to experience before moving from Trinidad.

Leatherback turtles are pretty amazing creatures. They have to be the closest thing to dinosaurs left on earth. They measure from 1 -3 meters long, about 2-3 feet tall, and about 3-4 feet across. They can also reach about 800-1200 pounds. I realize that I'm math teacher mixing measurement units - deal with it.


Here's the story of how these turtles lay their eggs...


When the sun sets and darkness falls across the beach, these massive creatures come out of the ocean, back to the very beach that they were born. When the eggs hatch, the hatchling turtles dig out of the sand and by the touch and smell of the sand, they know where they were born.

They find the beach by following the moonlight. This sometimes causes problems with hotels on the beach, because the turtles think the lights from the hotel are the moon. Apparently the turtles do not see (or are not effected) by red lights, so all the lights outside our hotel were red. Also the tour guides from the Trinidad Forestry Division have red head lamps to show you around at night. Most of my pictures were taken after dawn, when the last stragglers were on the beach.


After finding a spot that they feel is suitable, they start digging a hole with their back flippers. These flippers take out about 2 tablespoons of sand at a time. They go back and forth with each flipper, digging and digging, until they get a hole about 2 feet deep.


After they feel the hole is deep enough, they lay their eggs. They lay about 70 eggs and do this every 2-3 years after they mature. It takes about 15 years for the turtles to mature, and they can live to about 80-100 years old. About a third of the eggs that they lay (the last third) are infertile eggs. They do this because after the eggs are laid, they bury them with the sand and then compact it with their hind flippers. These infertile eggs act as a buffer to the fertilized eggs in case the sand crushes the eggs or if they get dug up by stray dogs, other turtles, birds, etc. While they are laying their eggs, the turtles go into a trance and this is when white light does not effect them and also when the Forestry Division will tag the turtle for data tracking and conservation purposes.

The picture above is the only picture in this series that was taken at night.

After the eggs are covered up by the hind flippers, the turtle then takes its front flippers and starts swooping back the sand around it to cover up and camouflage the nest. The span of these front flippers are about 6-7 feet when fully outstretched.

Once the turtle feels the nest is fully camouflaged, they head back into the ocean. The whole nesting process generally takes around 45-60 minutes. Although one that we watched at night was up for about 2 hours. She was really big and we guessed that she was a little more experienced with the process, so she was a little more careful about making sure her eggs aren't dug up by predators.


Look at that. Doesn't it look like some kind of ancient dinosaur? So cool.

Some other interesting things we learned about these leatherback turtles is that they have some of the softest shells of all sea turtles. This is because their defense against predators in the ocean (sharks, whales, boats, etc.) is to dive to extreme depths in a short amount of time. They can descend to 100 meters in 6-7 seconds. This is close to the length of a football field, including 1 end zone.

Being a diver now, I can attest to the pressure that can be exerted if proper measures are not taken to equalize when you descend. If the turtles did not have a softer shell, the pressure of the depth would crush their shells.

This had to be one of the coolest things that I've been able to experience while living here. And it was also kind of cool that we were there on Mother's Day.

1 comment:

Anonymous said...

loved the photos!