One More Threat for the East Pacific Leatherback

Upon arrival for my second field season with The Leatherback Trust in Costa Rica, I was eager to return to Playa Grande for its unique biodiversity. Playa Grande’s pristine white sand beach hosts nesting leatherbacks, the same species who swam our oceans 110 million years ago when dinosaurs roamed the Earth. Now critically endangered, East Pacific leatherbacks are protected within Las Baulas National Park, along with 127 species of birds and a diverse array of amphibians, reptiles and mammals frequently found along this vibrant coastline.

Daytime walks along Playa Grande always present something exciting, whether giant impressions made the night before by leatherback turtles creating “body pits”, hatchlings making their way from nests above the high tide line down to the ocean, or the sound of howler monkeys in the dry forest fringing the beach. This year, as I reveled in the stunning environment around me that Las Baulas National Park was created to protect, I also noticed many dogs on the beach.

The dog had a collar, indicating that it was a pet that had been left unleashed with its owner nowhere to be found. The leatherback hatchling appeared to have sustained serious injuries with puncture wounds from the dog’s teeth. It would not survive.

Lauren Hackney

Costa Rican National Park System Law No. 6084 and Las Baulas National Park Regulation D.E. 36918-MINAE, dogs are strictly prohibited on the Park’s beaches, including the 4.7 km stretch of nesting beaches designated as critical habitat for nesting leatherbacks at Playa Grande and Playa Ventanas. Dogs pose a grave threat to turtle nests and hatchlings. A dog’s strong sense of smell easily allows them to locate nests deep in the sand. Their claws and jaws also put nestlings and hatchlings at risk. Even the most well-mannered dog, when left to wander the beach and follow its canine instincts, can dig up a nest or injure a hatchling making its way to the water.

Yesterday, as I walked along Playa Ventanas at dawn, I saw a dog pouncing on the sand near the vegetation line. As I approached, I found the dog was attacking a leatherback hatchling! Perhaps the dog was hungry or perhaps it saw the hatchling as a play object. When I chased the dog, it dropped the hatchling and retreated into the vegetation near a beachfront house. The dog had a collar, indicating that it was a pet that had been left unleashed with its owner nowhere to be found. The leatherback hatchling appeared to have sustained serious injuries with puncture wounds from the dog’s teeth. It would not survive. 

As a conservationist, I know that only 1 in 1,000 leatherback hatchlings will reach maturity. But that statistic does not account for increased threats presented by increasing human settlement around Las Baulas National Park, including the rising number of dogs on the beach.

Lauren Hackney

I also witnessed a dog capture and critically injure a leatherback hatchling in Las Baulas National Park last nesting season. The owner had been walking 100 meters behind the unleashed dog and did not even notice it had snatched up a hatchling from this critically endangered population of sea turtles until it was too late. It is a common sight to see dogs at Playa Grande and Playa Ventanas, digging holes in the vegetation line, a prime location for sea turtle nests. 

As a conservationist, I know that only 1 in 1,000 leatherback hatchlings will reach maturity. But that statistic does not account for increased threats presented by increasing human settlement around Las Baulas National Park, including the rising number of dogs on the beach. 

To protect the critically endangered East Pacific leatherback population from extinction, including their nests and hatchlings, we need everyone’s help to reduce the presence of dogs in Las Baulas National Park. First, we must distinguish the two types of dogs on Playa Grande: domestic and feral. ‘Domestic’ dogs are those with owners while ‘feral’ dogs may be fed by community members (or scavenge from their refuse bins) but do not have owners. Although feral dogs may have more freedom to wander beaches, domesticated dogs actually pose more of a threat to sea turtle nests. According to a study done at the Colola Sanctuary in Mexico, a feral dog will predate a nest to feed on eggs or hatchlings because it is famished, but once the dog is sated it will not search for more. Domestic dogs, however, will predate nests out of curiosity rather than hunger, and they will dig up nest after nest until they lose interest. Domestic dogs digging up nests out of curiosity may not even eat the eggs, but once a nest is uncovered it becomes vulnerable not only to the elements but also to attack by other predators (e.g., caracaras, vultures, raccoons, coatis). 

Many dog owners I’ve met on the beach have told me that they were unaware of Las Baulas National Park’s boundaries or restrictions on dogs within the Park. The Leatherback Trust worked together with MINAE to create and post 17 new signs at all major entrances to Las Baulas National Park. We hope that these signs will improve adherence to Park rules by reminding visitors and residents that walking dogs on the beach or letting dogs run freely within the Park boundaries endangers turtle nests and hatchlings.

Beachgoers can also help turtles by removing trash and food scraps from the beach, since the scent of food can attract predators, including feral or unleashed domestic dogs. Local community members can also help reduce feral dog populations by spaying or neutering existing feral dogs and keeping any pets that have not been spayed or neutered indoors or under supervision to prevent unwanted litters.

As a dog owner myself, I understand it can be disheartening to leave our furry friends at home when heading out for a walk on the beach. But the beaches in Las Baulas National Park are unique. They are not just another place to live or walk our pets. They are the last mass nesting beaches for a critically endangered species on the brink of extinction. For the well-being of the wildlife and sea turtle populations that depend on the Las Baulas National Park, let’s all do our part to keep the beaches safe for hatchlings by being responsible dog owners. Numerous causes have contributed to the decline of the East Pacific leatherback, but dogs are one more threat that this critically endangered population cannot abide.

This article originally appeared on National Geographic's Ocean Views blog