Sea turtles have been swimming in the Earth’s oceans for over 100 million years, making them one of the oldest reptile groups on the planet.
Long before humans walked the Earth—before the Himalayas rose, before the Atlantic Ocean existed in its current form—sea turtles were already navigating the globe. Their lineage stretches back roughly 120 million years into the Cretaceous period, when they shared the seas with mosasaurs, plesiosaurs, and ammonites. Every one of those apex predators is gone. The sea turtles are still here.
Survivors of Deep Time
Of the many marine reptile lineages that once thrived in Mesozoic seas, sea turtles are the only group that endured the Cretaceous–Paleogene (K–Pg) mass extinction event 66 million years ago—the same asteroid impact that erased the non-avian dinosaurs. That kind of evolutionary resilience deserves more than admiration. It demands our attention.
Built for the Open Ocean
Seven species of sea turtles exist today, spread across every ocean except the Arctic. They range from the massive Leatherback—which can exceed six feet in length and dive deeper than 1,000 meters—to the critically endangered Kemp’s Ridley, the smallest species, found primarily in the Gulf of Mexico.
What unites them is extraordinary biological design. Sea turtles cannot retract into their shells like their terrestrial relatives. Instead, their bodies are hydrodynamically flattened, their limbs have evolved into powerful flippers, and their physiology is adapted to a life spent almost entirely at sea.
Females return to land only to nest—often to the exact beach where they hatched decades earlier, guided by the Earth’s magnetic field in a process called natal homing. I witnessed this cycle firsthand when green turtle hatchlings emerged from the sand at Six Senses Laamu in the Maldives, scrambling toward the Indian Ocean within minutes of breaking through.
Critical Ecological Anchors
Each species fills a role that no other marine animal can replace:
Remove any one of these species, and the downstream effects ripple through marine ecosystems in ways scientists are still working to fully understand.
Encountering Sea Turtles
There is a specific quality to seeing a sea turtle in the water that separates it from almost any other wildlife encounter. They are fundamentally unhurried. They move with a calm, deliberate rhythm—a few slow beats of their front flippers, then a long, effortless glide. Whether you’re watching from a snorkel, a dive mask, or even a boat, the effect is the same: time seems to slow down around them.
Get too close and they accelerate away instantly. Hold still and they often circle back—sometimes close enough that you can see the individual scutes on their shells, the texture of their skin, and the ancient, unbothered gaze of an animal whose ancestors watched continents drift apart.
I have been fortunate enough to encounter sea turtles across dozens of countries and multiple oceans. I’ve watched a curious green turtle make a graceful approach directly toward my lens in St. Eustatius, and I’ve filmed a resilient sea turtle navigating the reefs of Cozumel with a missing limb. But one moment in particular stays with me.
Off the coast of Tofo Beach in Mozambique, I came across a curious sea turtle that seemed far more interested in my camera housing than in swimming away.
Mozambique’s waters are part of the critical Western Indian Ocean migration corridor—a vital highway for species moving between far-flung feeding and nesting grounds. Encounters like this one remind you that these animals have been making these epic journeys for millions of years, long before humans ever drew a map of the coastline.
A 120-Million-Year Record Under Threat
Despite surviving asteroid impacts, ice ages, and the rise and fall of countless predator lineages, sea turtles now face threats that operate on a fundamentally different, accelerated timescale. The problems are not geological—they are human.
Sea turtles—Leatherbacks especially—mistake drifting plastic bags and film for jellyfish. Ingested plastic blocks digestive tracts, reduces nutrient absorption, and can be fatal. Global studies estimate that over half of all sea turtles worldwide have now ingested plastic debris.
Beachfront construction destroys ancestral nesting grounds. Artificial lighting disorients hatchlings, pulling them inland instead of toward the sea. Rising sand temperatures skew sex ratios through temperature-dependent sex determination, producing disproportionately more females and critically fewer males.
Commercial fishing operations remain the single largest source of direct mortality for many populations. Trawl nets, longlines, and gillnets kill hundreds of thousands of sea turtles every year.
What You Can Do
You don’t need to be a marine biologist to make a difference. Whether you encounter sea turtles while snorkeling on vacation, live near a nesting beach, or simply want to reduce your impact from home, there are concrete steps that help.
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Give Them SpaceIf you encounter a sea turtle in the water or on a beach, keep your distance. Chasing, touching, or crowding a resting turtle causes stress and can force it to abandon critical feeding or nesting sites.
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Report SightingsMarine conservation groups track turtle populations using public data. Clear photos of facial scute patterns—which act as unique fingerprints—contribute directly to population monitoring and research.
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Cut Out Single-Use PlasticsEvery piece of plastic kept out of the waste stream is one less hazard a Leatherback might mistake for a meal. This isn’t symbolic—it’s direct cause and effect.
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Support Responsible TourismChoose tour operators, resorts, and dive shops that enforce no-touch wildlife policies, limit group sizes, and actively participate in local conservation. Your spending decisions shape the industry.
Sea turtles did not survive 120 million years of geological upheaval by accident. They are incredibly resilient, highly adaptable, and ecologically irreplaceable. But evolutionary resilience has its limits. The question is no longer whether sea turtles can survive—they have already proven that. The question is whether we will let them.
Frequently Asked Questions
How long have sea turtles existed?
Sea turtles have existed for approximately 120 million years. Their lineage traces back to the Cretaceous period, meaning they coexisted with dinosaurs and survived the K–Pg mass extinction event 66 million years ago.
How many species of sea turtles are there?
There are seven recognized species: the Green, Loggerhead, Hawksbill, Leatherback, Olive Ridley, Kemp’s Ridley, and Flatback sea turtle. They are found in every ocean except the Arctic.
Are sea turtles endangered?
Five of the seven species are globally listed as Vulnerable or Critically Endangered by the IUCN. The green turtle was downlisted to Least Concern globally in 2025 following sustained conservation gains, while the flatback remains Data Deficient. However, many regional subpopulations of green turtles remain threatened, and all six species found in U.S. waters are protected under the Endangered Species Act.
What is natal homing in sea turtles?
Natal homing is the ability of female sea turtles to return to the exact beach where they hatched to lay their own eggs. They navigate using the Earth’s magnetic field and can travel thousands of miles to reach their birth beach decades later.
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