Green sea turtles are classified as endangered, threatened by overharvesting of their eggs, hunting, ocean plastic pollution, getting caught in fishing nets, and loss of habitat on their nesting beaches. Green sea turtles are found mainly in tropical and subtropical waters, and travelers on Nat Hab’s Florida nature tours have the chance to see them in Sanibel Island’s J.N. Ding Darling National Wildlife Refuge, Ten Thousand Islands’ Rookery Bay National Estuarine Research Reserve, and the Key West National Wildlife Refuge.

Here are 13 green sea turtle facts to know before you go!

1. How big are green sea turtles?

Green sea turtles are the largest hard-shelled marine turtle in the world and can grow to 5 feet and weigh up to 500 lbs.

2. What do green sea turtles eat?

Unlike most sea turtles, adult green sea turtles are herbivorous, feeding on sea grass and algae. Juveniles, however, also eat invertebrates like crabs, jellyfish and sponges.

3. Key link in the marine food chain

Sea turtles fill an important ecological role in ocean ecosystems by controlling prey species and themselves providing food to larger predators such as fish, sharks and birds.

4. What makes green sea turtles green?

The green sea turtle’s carapace, or shell, is usually brown or olive. Their name comes from the greenish color of the fat beneath their skin, due to the algae and grasses they eat.

5. Older than dinosaurs

Sea turtles are reptiles whose ancestors took to the sea about 150 million years ago. They are one of the few species so ancient that they watched the dinosaurs evolve and become extinct.

6. No place to hide

Like other sea turtles, the green turtle cannot pull its head into its shell.

7. How fast can green sea turtles swim?

On land, turtles are slow, but in the water, their powerful flippers allow them to swim gracefully at speeds up to 35 mph!

8. Sun seekers

Occasionally seen sunbathing alongside seals and albatrosses, the green sea turtle is one of the few marine turtles known to leave the water other than at nesting times.

9. Where do green sea turtles live?

Though marine turtles live in every ocean but the Arctic, green sea turtles live in tropical and subtropical waters and are commonly found (except when migrating) inside reefs, bays, and inlets.

10. Baby green sea turtles face a dangerous journey

Female turtles dig a pit in the sand, fill it with a clutch of 100 to 200 eggs and return to the sea, leaving the eggs to hatch after about two months. Babies hatch at night to avoid predators, but many never reach the sea.

11. Do sea turtles cry?

Green sea turtles possess a salt excretory gland at the corner of the eye. They may look like they’re crying, but they’re really adjusting their body’s water balance.

12. Boy or girl? How to predict

The hatchlings’ gender depends on the sand temperature. Less dense, warmer sand decreases incubation time and results in more female hatchlings.

13. World Wildlife Fund’s work with sea turtles

WWF’s work on sea turtles seeks to reduce the loss of turtle habitat, the negative impact of bycatch on turtles and illegal trade in turtle products such as meat and eggs. WWF works to protect nesting beaches, promotes ecotourism at sea turtle sites that involves and benefits local communities, lobbies for turtle-friendly fishing practices and supports regional and international agreements to conserve marine turtles.