Green Sea Turtle

Chelonia mydas

Black Sea Turtle

Chelonia mydas agassizii

Scientific Classification

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Family: Cheloniidae

Species Description

Adult Weight: 136 - 199 kgs (300 - 440 lbs)
Adult Size: 0.9 - 1.2 m (3 - 4 ft)
Appearance: Rounded head, greenish-black coloration, smooth domed carapace with teardrop shape
Diet: Seagrasses, mangrove leaves and shoots, jellyfish and algae

Natural Lifespan: 60 - 70 years
Age at Sexual Maturity: 20 - 50 years
Average Clutch Size: 70 - 200 eggs
Average Clutches per Season: 3 - 9 clutches
Nest Incubation Period: 45 - 75 days
Remigration Interval: 2 - 4 years

Life Cycle


Geographic Range: Mostly in tropical zones, less often in subtropical zones, worldwide.

Marine Habitat Use: Coastal waters, bays, estuaries and inlets with abundant marine algae and seagrass.

Juvenile green turtles disperse into pelagic and neritic habitats along the continental shelf where they feed on a wider diet including invertebrates before returning to coastal waters and adopting a mostly herbivorous diet as adults. Whereas many species of sea turtle thermoregulate by spending time in warmer waters in the shallows or at the surface, East Pacific green turtles are known to haul out of the water and bask onshore in protected areas.


Green turtles earned protection under many treaties and laws worldwide to address declines associated with direct consumption of meat or eggs. Although nest poaching has decreased due to community monitoring, illegal hunting of green sea turtles for personal consumption or sale within informal markets remains a challenge in many areas. Fishers likely to release other bycaught species of sea turtles may be reluctant to let green sea turtles go when they fetch a high price locally. Demand for green sea turtle meat may increase in countries where Catholicism is practiced as a substitute for other forbidden meats on Fridays during Lent.

Fun Fact

Green sea turtles have serrated beaks specially evolved to aid in consumption of seagrass. Active grazing by sea turtles keeps seagrass beds healthier and aids in carbon uptake by seagrasses