Sea Turtle Ecology

Leatherback Late Night
by -- April 23rd, 2013

After an early wake up call, we caught the 6:30 am ferry from Culebra to San Juan. We had planned on checking our luggage in early so that we could explore Old San Juan, but unfortunately we were not allowed to check them in until three hours before our flight. Therefore, we spent about eight hours lounging in the San Juan airport. We ate lunch, entertained ourselves with our iPads, and attempted to sleep on our suitcases. Eventually, we boarded the tiny plane and had a short flight to St. Croix.

Once we arrived at the cottages, we relaxed on the porch by the beach and devoured our roti! Soon enough, it was time to start getting ready for the long night ahead with forecasted rain. At 7:45 pm sharp, the Emmas, MB, Kelly and Wendy left for the reserve at Sandy Point. We were the first group to take on overnight monitoring for nesting activity and were anxious to get started. Once we made it onto the beach, we met Justin, Liz, Molly, and Jacob, who are all researchers working on the project. We split up into two groups, and started heading in opposite directions along the shore. Within our first hour of walking and waiting at certain markers, we were all called down because one group spotted a turtle. It ended up being a large green turtle, and its size as an adult surprised us after handling juveniles with so much ease on the boats in Puerto Rico. The turtle team suspected that she was a straggler from the previous season. We were unable to observe the entire nesting process with the green turtle because it ended up abandoning the construction of the nest chamber and returning to sea without laying eggs.

Shortly after leaving the green turtle, my group spotted a leatherback! The Emmas were struggling to contain their excitement, as we squeezed each others’ hands, jumped up and down, and walked even faster than we would for a big bag of Doritos. Not only was the enormity of leatherbacks shocking at first, but we were continuously in awe of its size throughout the rest of the night. We also found surprising the turtle’s grunting, burping, and heavy breathing. It was very interesting to immerse ourselves in the field and learn about the nesting process firsthand from start to finish. First, the turtle makes a body pit by flapping its flippers back and forth, as if it is making a sand angel. After a while, it creates an egg chamber by digging a deep hole that is much smaller than the body pit. When the leatherback is ready to lay eggs, she will subtly cover her cloaca with one of her back flippers and begin ovipositing. There is a mix of yolked and yolkless eggs in each clutch; some researchers suggest that the role of yolkless eggs is to fool potential predators that might otherwise eat the real eggs. Fortunately, we were able to hold some of the eggs and found them surprisingly pliable yet protected enough by the amount of fluid inside of them. After all of the eggs are laid, the turtle covers the egg chamber with sand using her back flippers and she tamps it down so that the area is more compact and inconspicuous. The turtle then uses her front flippers to cover the entire nesting area with a lot of sand. Some turtles spend more time on this stage than others, but it is generally the most tedious part of the process. She scooches herself along to different areas away from the eggs and covers everything with sand to camouflage the egg zone. After much time and effort, the leatherback zigzags back toward the shore. Perhaps she does this to further confuse predators and lead them astray from the nest. We were extremely satisfied and impressed when the turtles made it back into the ocean.

In one case, we relocated the eggs because the nest was in the erosion zone and thus the eggs were in danger of being exposed and destroyed by wave action. Liz placed herself right behind the turtle’s back flippers, and each time after a few eggs were laid, she grabbed them and put them in a plastic bag. Justin dug a very impressive and perfectly round hole resembling a turtle nest cavity, located closer to the vegetation, and gently placed the eggs inside of it then covered the area with sand.

There was also a large educational group at Sandy Point in the beginning of the night. It was led by the “Turtle Team” and its members were of a wide age range. The Turtle Team explained the steps of the nesting process to the group and allowed everyone to take turns petting the turtle’s “pink spot” on top of its head. The pink spot is thought to be located directly above the turtle’s pineal gland. From pink spots to egg chambers, both the educational group and my small group of undergrads felt extremely lucky to have the opportunity to observe everything that we did.

One last look at our house in Puerto Rico

Front sign of the Cottages By The Sea in Frederiksted, St. Croix

View of the beach right outside of our cottages

©2016 Nicholas School of the Environment at Duke University | Box 90328 | Durham, NC 27708
how to contact us > | login to the site > | site disclaimers >

footer nav stuff