The only sea turtle that's primarily herbivorous as an adult — and the largest of the hard-shelled sea turtles, reaching 350 pounds. The "green" refers to their fat, not their shell.

Native status: Native; circumglobal in tropical and subtropical seas

§ Quick facts

SizeCarapace 80–100 cm (31–39 in)
WeightAverage 135 kg (300 lb); largest documented 450 kg
LifespanEstimated 50–70 years
OrderTestudines
FamilyCheloniidae

§ Encyclopedia

The green sea turtle, also known as the green turtle, black sea turtle, and Pacific green turtle, is a species of large sea turtle of the family Cheloniidae. It is the only species in the genus Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans, but it is also found in the Indian Ocean. The common name refers to the usually green fat found beneath its carapace, due to its diet strictly being seagrass, not to the color of its carapace, which is olive to black.

Source: Wikipedia — Green sea turtle Licensed under CC BY-SA 4.0

§ Identification

Field marks. Smooth olive-brown shell; round head; serrated lower jaw. Named for greenish fat (not shell) from seagrass diet.

Similar species. Loggerhead (large head, reddish shell). Hawksbill (overlapping shell scutes, raptor-like beak).

Voice. Hatchlings communicate inside eggs to synchronize hatching. Adults silent.

§ Diet & behavior

Diet. Juveniles: omnivorous (jellyfish, crabs, sponges). Adults: almost entirely herbivorous, grazing on seagrass and algae — the only fully herbivorous sea turtle.

Behavior. Migrates 2,500+ km between feeding grounds and nesting beaches. Females return to natal beaches to nest every 2–4 years, digging deep holes for ~100 eggs.

§ Range

Tropical and subtropical waters worldwide; nests on US Atlantic and Pacific beaches

§ Habitat

Coastal seagrass beds, coral reefs, lagoons; sandy beaches for nesting

§ Threats

Plastic ingestion, light pollution disorienting hatchlings, fibropapilloma tumors linked to water quality, climate-driven beach loss.

§ Conservation status

According to the IUCN Red List, the green sea turtle is currently classified as Endangered.

§ What helps

Reduce single-use plastics. Use turtle-friendly amber lighting near beaches. Support Marine Protected Areas with seagrass.

Support our work More ways to help

§ Further reading

§ Sources cited

  • NOAA Fisheries
  • Sea Turtle Conservancy
  • USFWS
  • IUCN Red List 2004