Tuesday, February 21, 2012

Early Leatherbacks Hit Our Beach!

Leatherback Half Moon

We’ve just seen our first Leatherback half moon tracks of the season. This is exciting news, as it (along with a Green Sea Turtle nest that we saw as well, and two Leatherback nests along the beach by the Jalova base) ushers in the start of this year’s Sea Turtle season. What is a half moon, you may ask? That’s a good question, and one that I only learned the answer to a month ago when I first arrived here. A half moon is one of two kinds of turtle tracks we expect to see on the beach during nesting season. When a turtle comes up out of the water to nest, it will either come all the way up the beach to dig its nest and then head back to the water; or it will come partway up the beach, and then for any of several reasons will return to the water without having laid its eggs. This second occurrence, which generally happens when the turtle feels threatened or unsafe to dig its nest, leaves a large crescent in the sand, marking where the turtle has emerged from the water, changed its mind about nesting, and turned to head back to the sea. This is what we call a half moon track.

Volunteer Grace stands next to the Leatherback track

Turtle tracks are extremely distinctive: the turtle drags its huge weight (Green Turtles weigh between 144-450 lbs, or 65-204 kg, while Leatherbacks can weigh between 550-2000 lbs; that’s a whopping 250-907 kg!) along by its flippers, creating a straight line at the center from the carapace as it is dragged through the sand, framed on either side by outward-splayed gouges in the sand from the turtle’s flippers. The Green Sea Turtle tracks are 2 to 3 feet in width, already quite wide; but the Leatherback tracks are huge. I could have stood in the center of the half moon track and held my arms out to either side (I have an arm span of 65 inches, or 165 cm) and only barely matched the width of the Leatherback from flipper to flipper.

Green Sea Turtle Tracks

I’d like to be able to take credit for spotting this particular halfmoon track, but embarrassingly I have to admit that I didn’t even see it until I was practically past it. All three of us out on our survey that morning were scouring the upper beach for jaguar tracks, and completely failed to notice the huge turtle tracks lower down on the beach. Only Leo, our survey leader, noticed them and called us back – we stood in awe of the huge track marks for a while (and also in awe of our apparent inability to note something quite that huge and distinctive on the beach) before moving on with a feeling of excitement at our (well, Leo’s) great find.

-Holly, GVI intern