Thursday, May 26, 2011

Leatherbacks

            I’ve decided to change things up a little with this post.  Rather than composing a new entry, I’m basically posting a letter I wrote to my parents back in 1987.  I’ve edited it a little for grammar and tense, although I thought it stood by itself pretty well.  But first a little background.  In 1987 I was a senior veterinary student at Purdue University in search of a practice with which to serve my externship.  My sister, Dianna, was then living in St. Croix in the US Virgin Islands and took it upon herself to contact the local veterinary clinic there.  A very generous Crago Animal Clinic gave me the opportunity to spend nearly two months in paradise, but I just look at it as a sacrifice for my education.  Many opportunities were opened to me.  Mornings were spent at the clinic, but afternoons were spent lounging on the beach and snorkeling the crystal clear waters off Cane Bay.  There was Carnival on St. Thomas and Easter on St. John.  However, one adventure stands above all others.  My sister, being the bold adventurer of the family, arranged for her and me to spend a night with an Earthwatch group who was studying nesting Leatherback sea turtles on the southwest corner of the island.  What follows is my account of that evening.  I want to stress that this is not meant as a scientific treatise on leatherback turtles, and I have done nothing to verify the information included.  It is simply my recollection of statements I had heard that night on the beach.  So with that in mind, here is my great turtle adventure.
April 14, 1987
            Last night Dianna and I had the chance of a lifetime- to participate in a turtle watch for nesting leatherback sea turtles.   St. Croix is one of about half a dozen nesting sites in the Virgin Islands and one of about a dozen sites worldwide.  This particular beach holds the distinction of attracting the largest nesting population of leatherbacks in US waters.  The beach, Sandy Point Beach near Frederiksted, is ideal for these turtles.  It is a long stretch of sand with deep water access.  There are no rocks or coral reefs to interfere with the turtles’ approach and the area has been classified as a nature preserve.  Last night we had an additional bonus (at least initially) of a full moon which illuminated the entire strip of beach with a soft, silver light.  Spotting a turtle would be easy.
            Our leaders for this event were a pair of biologists who give up six months of their lives to aid and document the nesting and hatching of these turtles.  Ten hours a night, seven days a week, these two scientists, along with a group of Earthwatch volunteers, patrol this beach, collect data and play host to groups of interested onlookers such as us.  The plan last night was to position Dianna, myself and about seven other individuals who had come along to watch in the center of the beach.  The Earthwatch volunteers would move on down to the far end until 9:00 at which time they would walk the length of the beach in search of turtles.  If no turtles were seen, they would reposition themselves at the opposite end of the beach until the following hour when they would again make the patrol.  Dianna and I had decided to walk the beach for a while and soon found ourselves sitting with the Earthwatch group listening to turtle facts.  At about 8:30 we decided to continue our walk along the shore.  We had moved about 100 yards up the beach when I noticed a large black form emerging from the water.  The rush of adrenalin was incredible, and it took a lot not to run right up to the turtle.  The signal for a turtle was to be three flashes with a flashlight to be answered by one flash from the other group; however, I had left our flashlight with one of the people in our group so I had to run back down the beach to the Earthwatch group.  Shortly, there were a dozen people standing in silence in the moonlight watching this lone creature heave her body along the sand.
Dianna and I admiring turtle
            We kept our distance as she climbed the beach so she would not be frightened and return to the sea.  It is amazing how quickly these giant animals can move through the sand, and it took little time for this female to choose a spot near the vegetation line to dig her nest.  We could see sand flying into the air as she began body molding, the process of shifting her body and digging with her flippers until she makes a depression in the sand large enough to fit her body.  Then slowly and methodically she began the process of digging the primary hole into which she would lay between 60 and 100 eggs.  She would carefully push one of her rear fins into the sand, curl it under her, and then bring out a “handful” of sand.  This continued until a shaft three feet deep was created.  This particular female had chosen a very dry area so the hole periodically caved in slightly and was partially filled.  It was our fear that she would have to abandon this site and seek out a more suitable patch of sand, but she stopped shifting her body and patiently continued her dig until a suitable hole was created.
            Finally, she grew quiet and covered the hole with her rear fins. This was the signal that she was about to begin laying eggs.  At this point instinct and maternal drive become so strong you can handle them with the female apparently oblivious to everything around her.  This is when the Earthwatch team sprang into action.  Her length (about five feet) and width (about three feet) were recorded.  One woman recorded all distinguishing marks on a prepared diagram of the turtle.  Her rear fins were pulled aside and nest depth was measured and recorded.  Dianna helped another volunteer count the eggs as they were laid.  The eggs themselves look like the cue ball in a pool game- white, round, glistening but with a pliable shell which allows them to survive the long fall to the sand.  She would strain slightly and then two or three eggs would shoot out into the nest.  This continued for nearly 20 minutes until the yokeless eggs (small, infertile eggs that are thought to aid in maintaining the moisture of the nest) appeared, marking the end of the lay.  Soon she would begin to push sand over the eggs creating a slight mound.  She would make several other mounds to disguise the actual nest site.
The pink spot (3rd eye) is visible here. 
            The leatherback turtle is quite a sight to behold.  Her shell is very smooth but has a series of ridges running its length which makes it appear very much like the hull of a small boat turned upside down.  The shell is relatively soft giving rise to the name “leatherback.”  She is black with white streaks along the ridges of her shell, and she has a large pink spot on the top of her head which is believed to be a light sensor or “third eye.”  With some individuals, missing fins and scarred flesh tell the tale of narrow escapes from sharks and killer whales, the natural predators of adult leatherbacks.  Because of her massive size and inability to expand her shell, breathing is quite labored.  She must arch her neck forward and upward to draw in a loud, slow gasping breath.  Hearing that sound coming from this prehistoric creature on a lonely beach in the dark of night is an eerie yet exhilarating experience.  Because she takes in so much salt, the leatherback has developed a means of eliminating the excess salt through a constant stream of tears.  Although this is a continuous process, the tears are especially evident when the turtle is on land.  Because of their thick, viscous nature the tears hang from the turtle’s eyes giving the impression that she is crying.   She may be five or six feet long and from fin tip to fin tip may be eight feet wide.  Last night we had the privilege of assisting in the first attempt ever made by this this team to weigh a leatherback.  They erected a large tripod over her and passed two straps beneath her through tunnels they had dug in the sand.  The straps were attached to a scale suspended on a series of pulleys.  Then with people steadying the tripod we hoisted her into the air, her back fins still instinctively pushing invisible sand onto her nest.  The scale read 700 lbs.
Digging tunnel for strap
One strap in place.
            Seven hundred pounds is a pretty good sized turtle, but the team leaders talked of another turtle, “Snaggle Tooth” which also nested on this beach.  Snaggle Tooth, they said, was as big as they come and much larger than this female.  Suddenly, from the point- THREE FLASHES!  Another turtle had come ashore.  Immediately, Susan (the researcher with our group) and an Earthwatch volunteer headed down the beach to begin collecting data on the new turtle.  We continued to tag this female, one tag in a front fin and another in the rear fin.  This particular turtle had come ashore the night before but had turned back before laying any eggs or before they could tag her.  It was at this point that the radio crackled, “Earth-base ‘S’ to earth-base ‘B,’ we have the giant one down here.  She’s body molding right now so you’ll have time to make it down here and get a weight on her.”  What luck!  Other people had been out all week and did well to see one turtle (usually after 3 AM.)  Here it was only 9:30 and we had two turtles on the beach.  Not only that, but one of them was Snaggle Tooth herself.  The excitement started to mount, and we almost ran down the beach afraid in some way that we might miss this “legend.”  Not even the light rain which had started could dampen our spirits.
            She, too, was at the vegetation line, nosed up to a small tree.  At first she didn’t look much bigger than the female we had just left, but as we got closer the difference became obvious.  She was at least a foot longer and overall had a much larger build.  Her head was at least a foot in width.  Her nickname was well deserved since some early encounter had left her with half a lower jaw and a twisted, scarred face.  She would look up to breath and flash what looked like a crooked but endearing grin.  It can certainly be said that this grand old lady had character. 
A good shot of Snaggle Tooth's missing jaw.

            Although she was near the vegetation, her nest was near the water and in an area that would be prone to erosion, so the decision was made to relocate the nest.  This is where the measurement of nest depth becomes important.  Like many other reptiles the sex of the egg is determined by the temperature of its environment.  Since temperature varies with depth, it is essential that the eggs be placed at the same depth as that from which they were removed.  So as soon as she would lay some eggs, they would be snatched from the nest by an Earthwatch volunteer and placed in a mesh bag.  They would have two hours to select a new nest site and bury the eggs.  Then in 60 days the eggs will hatch, and hundreds of little babies only four inches long will push their way to the surface (again under the cover of darkness) where they will congregate until the entire clutch has emerged.  Then, oriented by the light of the ocean, they will clumsily make their way through a gauntlet of predators to the water.  Some will be killed by ghost crabs.  Others will fall victim to birds or dogs.  Still others will be trapped in tire tracks or hoof prints in the sand.  Those which do reach the water are met by hundreds of hungry fish.  It is easy to see how that for every one hundred eggs that hatch, only one hatchling will survive.
Bob with  a handful of eggs.
            Her laying complete, the moment of truth arrived.  We were about to weigh perhaps the largest leatherback to nest on this beach.  It would take everyone there to steady the tripod and hoist this massive animal into the air.  All the men took hold of the line and HEAVED!  Slowly, she began to rise from the sand.  HEAVE!  The tripod began to lean to one side.  HEAVE!  Even with the system of pulleys designed to lighten the strain, you could feel the immense weight on the rope.  HEAVE!  The tripod leaned even more, but her body finally cleared the sand.  Bob (the other researcher) read the scale and announced that she weighed 504 kg.  She was 1100 pounds and perhaps even more since her rear flippers may still have been on the ground.  Half a ton of turtle hung there in the rain, thick tears streaming from both eyes, that jawless grin flashing with each breath, and an odd assortment of people surrounding her, stroking her, measuring her, and photographing her.  And somewhere in the depths of the ocean swam her mate who is twice her size.  The only contact he’ll ever have with land was that perilous dash he made for the ocean following his emergence from the sand years ago.  Maybe he was born on this very beach or perhaps he came from Mexico or Africa.  No one knows much about the males since their life is spent in the deep ocean somewhere between the nesting site and Nova Scotia, which is where these females will soon be returning.
Author shining light on Snaggle Tooth's pink spot while Susan places numbered marker for photo.
            Snaggle Tooth was slowly eased back down to the beach where she continued her nesting ritual by filling in what was now an empty nest.  Despite our intrusion into her activities, she would return in 10 nights to repeat the process.  She may return as many as 10 times and then disappear for two years, when a new group of people will be lucky enough to witness this miraculous event.  I’m sure they too will long remember that jawless grin of this gentle giant.
            And we will also remember the dedication of this group of people who gave up so much to study and protect these animals.  Picture in your mind an 1100 lb. turtle slowly digging a nest on a dark beach.  It is raining, yet around this animal lies a dozen individuals on their stomachs peering into the ever deepening hole.  Few words are spoken, we are hypnotized by the sheer fortune of being a part of such a rare event with so special an animal.  It is an experience everyone should have in his/her life but so few ever will.
My sister, Dianna giving Snaggle Tooth a good bye stroke.
That was my letter home.  What I didn’t mention was how I slipped away from the group while they were working with Snaggle Tooth so I could go back down the beach for some alone time with the first turtle.  I sat in the sand and watched her rock her body to cover the nest and watched her build false nest mounds to disguise the real thing.  There was a second chance a week or so later for Dianna and me to follow the team, although this time we were accompanied by a photographer for National Geographic.  Not a single turtle showed up that night.  Recently reviewing Bob and Susan’s data from that summer, only 30 turtles nested on Sandy Point in 1987, and we were lucky enough to see two of them.  I am forever grateful to my sister for arranging this wonderful evening and for the Earthwatch team for letting us tag along.  How I would love to return and do this all over again.

I apologize for the quality of these photos.  My film was damaged in the camera (perhaps sand or salt got into it.)

4 comments:

  1. I like to hear about your stories from St. Croix. I know you suffered doing you internship there!
    Once in a lifetime opportunity!

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  2. What an awesome adventure! Thanks for sharing. Jody

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  3. Darlene ThompsonMay 28, 2011 at 10:27 AM

    Very cool, Dr. Fifer. It all just amazes me how nature works.

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  4. This is amazing Scott!
    I never realized how huge they are!
    Very very cool.
    Thank you so much for sharing this marvelous story!

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