02 February 2009

Tourists Save the Lives of 37

This extended cold weather has me thinking about warmer places.

In November 2007, Lindsay and I took a two week vacation to Costa Rica. Although birds and plants were our primary targets, a group of 3 inch long shelled reptiles in Tortuguero ("the region of turtles") stole the show.
We woke around 4 AM the morning of November 3 for a chance to see Green Sea Turtle (Chelonia mydas) hatchlings emerging from eggs and making their way to the Caribbean Sea. You're probably thinking, "Why would these lunatics wake up so early on vacation to see some silly turtles?" These aren't your ordinary turtles. Green Sea Turtles have a long history... in fact, there is evidence that they were around at the same time as the dinosaurs... and they have an even more interesting life history. More on that in a bit.

Green Sea Turtles can move fast - 35 mph, in fact, when swimming. That's not too bad for a reptile that can weigh up to 500 pounds when full grown. Another impressive fact is that they can go up to 2 hours without breathing when sleeping! Although juvenile Green Sea Turtles are carnivorous, adults feed only on plants. They spend most of their long lives (they have been known to live up to 80 years) in the water, covering nearly one thousand miles to get to feeding territories, but females have to be on land to lay eggs. Here's the amazing part... a Green Sea Turtle will go back to the same beach on which she was born at least 25 years previously to lay eggs! After building the nest and laying eggs, the adult female moves back to sea, leaving the eggs and hatchlings to fend for themselves. This is not at all an easy task for the young ones, considering the numerous predators (wild dogs, birds, crabs, etc.) that stalk the beaches looking for lunch. The eggs incubate for 2 months before the hatchlings emerge. When they emerge, they immediately head towards the sea, a trip that seems like a marathon and an obstacle course all in one.

That unforgettable November morning, we walked along the beach donning headlamps and wielding cameras with the sun still breaching the horizon. Our guide Rebecca examined numerous empty nests. Portions of egg shells were scattered in several places where either a wild dog had dug up eggs or turtles had already emerged.

Finally, Rebecca found a nest where she was able to feel turtle heads. She wiped the sand off of the top few turtles and they began the long journey of approximately 200 feet from nest to the Caribbean.

Due to the stresses mentioned earlier, only ~1% of the hatchlings actually survive. Individuals from our group walked with the newly emerged turtles as they made their way to the water. Then more turtles began to emerge. And more.

In the hour or so that we watched, 37 babies emerged from the nest and fought their way through footprints in the sand, over debris, and into the sea. This was a small nest; sometimes, up to 100 hatchlings will emerge.

It felt good to be the guardian for a few of these turtles for the first 20 minutes or so of their lives, but it was exhausting watching them make this arduous journey.


ben said...

Very cool! I got to watch some eggs being laid, but seeing the babies would be great.

Scott said...

Where were you when you saw the eggs being laid?