by Nancy Tankersley, Lead Biologist.
It’s 2 a.m. on January 20, one hour before high tide. The new moon has set, and only stars light the sky. The Sea Turtles Forever (STF) patrol team, dressed in dark clothes, walks onto Lagartillo Beach where resident patroller Martin Gomez is waiting for us with his nightly report. A female green turtle has just come ashore and started to dig a nest. He cautions us that there are some locals fishing near a campfire on the far south end, probably looking for an opportunity to take unattended turtle eggs. Martin, a former poacher, recently asked to become part of the STF conservation team, partly because STF pays more than he would earn poaching, and mostly because STF has been so successful in outwitting the poachers during the last 5 years of patrols. Turtle eggs are a traditional local food, but most are sold on the local black market as a natural (although mythological) aphrodisiac.
We turn off our headlamps, and walk in the starlight until crossing the turtle’s track from the ocean to the beach. Marc Ward, STF President and skillful field biologist, tells us to wait while he checks on her activity. These green sea turtles, an endangered species, are very sensitive to artificial lights and disturbance, so he uses caution in his approach. Reporting back, he tells us she has dug her nesting body pit and is starting to excavate an egg chamber in the sand with her rear flippers.
We wait about 20 minutes while sitting under the cover of a buttonwood tree (checking the area first for snakes and spiders). Our eyes have adjusted to the starlight, and now we are in awe of the bioluminescence igniting the waves. As a wave washes onto the beach at our feet, little stars of firelight glow and then fade as the wave retreats. I look up just in time to see a shooting star race across the dark sky, under the Milky Way.
Marc checks the turtle again and signals us to approach because she is just about ready to lay her eggs. She is roughly three feet long, dark green, with a large humped carapace. I marvel at her shell, which has its own array of stars – barnacles that have attached during the past 20 or more years as she migrated hundreds of miles between nesting areas and feeding grounds, perhaps after hatching nearby. Martin deftly digs his own body pit behind hers so he can lie down and catch the eggs as they emerge from her cloaca. Normally, they would drop into her egg chamber, about two feet deep, before she would cover them with sand.
We are able to use our dim red light headlamps now, because she is well into labor, and does not react to our presence. Her off-white, leathery eggs drop in groups of three or four, and we place them in a clean bag for transport to a new pit that Martin has excavated, away from the turtle tracks and hidden from any poacher. Two metal tags on her front flippers sparkle in our lights, placed by STF staff during a previous nesting episode. (Each female nests 3 or 4 times per season, every three to four years). From the numbers on her tags, we know her as “Hope,” tagged three years ago when she previously nested nearby. This is exciting documentation of our little-known population of endangered Eastern Pacific green sea turtles.
The eggs, beautiful round orbs, are counted(65), weighed (about the same as a kiwi fruit), and measured (diameters less than 2-inches), before we bury them nearby. We carefully disguise the site to look like the natural beach surface, and record the location with a GPS and physical description so that STF staff can check on the hatch, expected about 55 days later. Over the years, the STF team has learned how to rebury the eggs to produce a better-than-natural hatch rate, even up to 100%. Oblivious to the removal of her eggs, Hope finishes her ritual by flipping and packing sand over her empty nest chamber and body pit for about 45 minutes, and then pushes herself slowly back to the sea.
We continue our patrol down the beach, searching for more tracks as the high tide wanes. Old-timers have told Marc that 40 years ago, there were hundreds of turtles per night nesting in the 6-mile project area. But in the last 10 years, STF finds no more than three per night during the nesting season, often none. In the 1960’s, commercial fishing decimated the nesting turtle populations. And until STF started patrols, an unsustainable number of eggs were taken by poachers. When we reach the end of the beach, the poacher’s fire is dying. Because we found the only turtle that night first, they have gone home, knowing that all they would find now are her tracks with an empty nest chamber.
So far this season, the tally is poachers = 21 nests stolen, STF = 72 nests saved. When STF patrols first began 10 years ago, brazen poachers got almost all of the nests. Marc was reviled by many locals, and even attacked by five men while patrolling alone. But now, the remaining poachers have lost their upper hand, and operate more covertly and less successfully. After 10 years, the continuing presence of STF patrollers has turned the tide, turning poachers into protectors, and aphrodisiacs into tortugitas. We walk back to the trailhead, and I am in awe of the perseverance, courage, and skill of the stellar STF team. The Great Bear has set in the northern sky, and the Southern Cross has risen high, giving us hope that the green sea turtle population will rise again.
Many times over the last 23 years, when running monitoring and protection patrols for marine turtles in Costa Rica, I return to beaches alone, late at night, late in the tide. I check for aborted nests and possible false crawls (not uncommon—when a turtle arrives on a beach but turns right around and leaves). Sometimes I find a late nester and score a bonus nest, or maybe a hatching nest.
Lagartillo is situated on the north end of our Punta Pargos project. Raw jungle and beach meet a small river mouth and estuary to the south, a secluded home to crocodiles. At 3 am, I walked down to the river for a beach check. A lack of light pollution darkens the night here. Finding no new turtle activity, I walked back. And there, low and behold, where the jungle trail enters the beach, under a Buttonwood tree in the sand, I saw hatchlings crawling out to the sea. Buttonwood trees are a favorite turtle nesting habitat, often growing limbs right on the sand. A limb on my left, about six inches high, ran toward the ocean and created a small barrier, protecting the next to my right.
When a nest hatches, we collect specific data. We measure 10 hatchlings and weigh 10 hatchlings. Then we exhume the nest, count the eggs and how many have hatched. Often, there are a few undeveloped eggs and a few hatchlings that did not survive. We need this data to study hatch success rates and biometrics. This process is our volunteers’ favorite part. It can be emotional: the joy of new birth, and the satisfaction of success. Our hard work and many nights on patrol are paying off at this moment, with more endangered sea turtles heading out to sea. Otherwise, they would have been taken by poachers.
I knelt at the nest, took out my digital scale and calipers, and began recording hatchling weights and carapace measurements. I wore a Petzel headlamp but didn’t turn it on. The moon and starlight were enough.
Morning glory vines and Pinuella cactus dominate the back beach vegetation. Beach grass and underbrush grow below the endangered Buttonwood trees. During the dry season, the leaves have fallen and you can see through the tangle. I was halfway done with data collection when I heard a rustling to my left. It’s not unusual to encounter snakes and other animals on the beach at night. I’ve seen sloths, opossums, racoons, anteaters, jaguars, crocodiles, ocelots, and more. But what was this? Certain I had never seen this animal before, I turned on my headlamp to get a better look and paused. It stood still and looked back at me, about 10 feet away. We locked eyes. It was about twice the size of an opossum and had a similar facial structure: a long snout, short ears, and glittering, tiny dark eyes. But this was no opossum. Sharp, rigid spines five inches long covered its body, face, and tail. I could see through its long, thin white hair to light-colored skin. Its spikes and claws were colored like fingernails. Its teeth, long and sharp, evolved for shredding flesh. We stared at each other for a few seconds, then it bared its teeth and snarled viciously.
I always carry a five-foot bamboo staff while on patrol to defend against snakes and dogs, and to clear the spider webs when I am walking through the trees. I also use it to measure nest depths. I had my staff stuck in the sand about four feet behind me. I was on my knees, but when that animal began to growl at me, I sprang straight up and backward, landing with my right hand on my staff. I pulled it out of the sand and pointed the sharp end directly at the creature.
I don’t know how I pulled off a jump like that, but credit to my 30 years of martial arts training. This animal was charging me, but now, with my staff pointed at it like a spear, it stopped and crouched down, growling. We were at a standoff. I could tell it was contemplating attack, but instead it backed up slowly, one step at a time, always keeping its eyes on me as it retreated toward the vegetation line.
I was scared to death, but I had all of my gear on the sand by the nest, so I got back down to finish collecting data. I could still hear it running back and forth like a Tasmanian Devil in the dry leaves behind the cactus. Just inside the vegetation line 10 feet in front of me, it ripped back and forth at staggering speed a distance of five yards or so. I finished, picked up my gear and slowly walked north to the trail as the last hatchlings scrambled for the ocean.
This nocturnal predator wanted those hatchlings, and it probably would have eaten them all if I was not there. I came between it and its meal for the night. That, along with my direct eye-contact and challenging stance, its aggressive behavior made sense.
Several nights prior, I was walking down the jungle trail to Lagartillo with my wife, Rachel, and our patrol team leader, Joseph Beshore, when we heard something running through the leaves next to the trail. About 10 feet away, we saw a white flash heading toward the beach. I’ve never seen anything move that fast before—faster than an Armadillo. After a “What the hell was that?” moment, we went on to the beach to patrol and didn’t think more about it. But now…
I made a sketch of the creature when I got back to the field station. Then I started asking everyone I knew if they had ever seen anything like it. I looked through every book I could find and scoured the internet searching a species name. I asked numerous Costa Rican field biologists—no one has ever encountered such an animal. I’ve been on that beach at night at least 1,000 times, yet I’ve only experienced this one face-to-face encounter. Likely, one biologist said, this animal is new to science.
I’ve been surrounded by a poaching party of ten men. I’ve been shot at. I’ve had five poachers jump me. I’ve had snakes chase me, and I’ve stumbled upon crocodiles in the dark. But nothing has ever scared me like this. For many nights on patrol, I couldn’t ignore my nerves when I walked the jungle trail down to this beach. That night, this unknown creature evoked the supernatural. The cryptic. It deeply frightened me.
Hundreds of patrols have walked by since on this beach, but no one has encountered this strange animal again. I am still on high alert every time I visit. Even though I was terrified, I have always hoped for another encounter. That’s what I love about science: there are always new discoveries to be made.