Green Sea Turtle
Chelonia mydas
The sea turtle that eats its greens — and one of the ocean's great comeback stories.
The green turtle is named for the colour of its fat, not its shell, which can be olive, brown, grey or almost black. It's the only sea turtle that grows up to live mostly on plants, grazing on seagrass and seaweed. On Mexico's Pacific coast the green turtles are so dark that people call them black turtles, and the lagoons of Baja California Sur, like Bahía Magdalena, are some of their favourite places to feed.
On the conservation status
Moved from Endangered to Least Concern by the IUCN in October 2025, after nesting numbers climbed in many places, Mexico included. Scientists warn it will only stay that way if the protection continues.
- Length
- About 1–1.2 m (3–4 ft)
- Weight
- 110–180 kg (250–400 lb)
- Lifespan
- Probably 70 years or more
- Diet
- Seagrass and seaweed, plus some animals
- Grown up at
- 25–35 years old
- Class
- Reptile — not a mammal
The good stuff.
Named for its fat
Green turtles got their name from the greenish colour of their fat, not from their shells. It comes from all the plants they eat.
Ocean lawnmowers
Young green turtles eat almost anything. Grown-ups switch mostly to seagrass and seaweed, and by grazing they keep seagrass meadows short and healthy. In the eastern Pacific, they also eat more animals than green turtles elsewhere.
Black turtles
Along the Pacific coast of the Americas, green turtles are so dark they're known as black turtles, or tortuga prieta in Mexico. Many hatch on beaches in Michoacán, then swim north to feed in the lagoons of Baja California.
Back from the brink in Mexico
So many black turtles were caught for their meat in the 1960s and 70s that by 1988, fewer than 200 females were nesting on Michoacán's main beaches. Mexico banned catching sea turtles in 1990, local people guarded the nests, and the turtles came back.
Home to lay eggs
Every two to five years, a female swims back to the coast where she hatched to lay her eggs. She comes ashore about every two weeks during the season, laying around 110 eggs each time.
Measured in Baja since 2001
Every month since 2001, Grupo Tortuguero, a network of scientists, fishers and families, has been catching, measuring, tagging and releasing green turtles in Bahía Magdalena and other lagoons, to keep track of how they're doing.
Wait, really?
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There are around 28% more nesting green turtles now than in the 1970s.
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In Hawaii, green turtles haul themselves up onto beaches just to rest in the sun, which few sea turtles do.
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A hatchling is about 5 cm long, small enough to sit in your palm.
What it sounds like
Mostly quiet. Adult green turtles aren't known to call to each other, though scientists have recorded faint sounds from the eggs of several kinds of sea turtle just before they hatch.
We haven't found a recording we're allowed to share yet, so for now this one is a description.
Where you might see one
The lagoons of Baja California Sur, like Bahía Magdalena, where they feed; the beaches of Michoacán, where black turtles nest; and Hawaii, where they rest on the sand.
The trouble
- Getting caught by accident in fishing nets
- Illegal hunting for meat and eggs
- Plastic, which they mistake for food
- Lost seagrass meadows and nesting beaches
One real thing
Never buy turtle meat, eggs or shell: in Mexico it has been illegal since 1990. On a nesting beach, keep your distance, keep lights off at night, and fill in any holes you dig in the sand so hatchlings don't get stuck in them.
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