Recently I visited Las Baulas National Marine Park in Guanacaste, Costa Rica. But I didn’t see a single one of these leatherback turtles that the park is named after (baula is the Spanish word for leatherback sea turtle). It’s because after surviving for more than 100 million years, Pacific leatherbacks are now critically endangered. My guide told me that 20 years ago there were around 1,800 nesting females in the area. Now: 200.

The overall the population of nesting female leatherback turtles is around 20,000 to 30,000. The Pacific leatherback is the most endangered with only 2,300 nesting females left.

I would have loved to see this anomalous creature in the flesh, with its leathery shell that sets it apart from other sea turtles. Adult females can grow up to six feet long! So this is a real life beast, one of the closest things to a dinosaur still roaming the earth. Their main niche in marine ecosystems is keeping jellyfish populations at bay.

There is a double-edged sword to the developing tourism industry in Costa Rica. In Guanacaste, many locals depend on tourism jobs for their livelihood. In fact, some who used to poach leatherback eggs have been able to atone by training with the national park as eco-tour guides. But still, coastal development and human activity have disturbed nesting beaches, not only here in Guanacaste, but in other areas of the Coral Triangle where leatherbacks nest. Just in Las Baulas, the local guides are pretty conflicted over the situation. They are deeply connected to nature, but have to make a living in a rising economy where they have to shop from the same markets as expats and foreign tourists. One said to me that coastal development and tourism are “good for work, but bad for nature.” Unsustainable fishing such as shrimp trawl nets, longline hooks, and gillnetting are also a hazard to sea turtle populations, resulting in these epic reptiles being caught as bycatch and drowning.

So what can we do to help? First thing: absolutely avoid littering. I’m not just talking about on the beach – anything you throw on the ground, anywhere, could end up in the ocean. Pieces of plastic have been mistaken as jellyfish by baby leatherbacks. Participate in coastal clean ups – internationally with Ocean Conservancy, or in California with Heal the Bay. If you’d like, you can pick up trash on the beach by yourself, anytime (just avoid using plastic bags if you can). Second, be mindful of fishing methods used for the fish you purchase. Swordfish, tuna, shark and shrimp specifically may have been caught using methods that lead to sea turtle bycatch. Use Seafood Watch as a resource for this. Last, you can support the Leatherback Trust or the World Wildlife Fund.

So much remains a mystery about these animals that bravely disappear into the open ocean as hatchlings, re-emerging only after maturing at 15-25 years. With conservation efforts, maybe this ancient species can live for 100 million years more.