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Green Sea Turtle

Chelonia mydas

Family: Cheloniidae

COSEWIC status:
  • Not Assessed
SARA status:
  • No Status
IUCN status:
  • Endangered


The Green Sea Turtle can attain a maximum carapace length of 1.5 m, but most individuals are much smaller than this. The “heart-shaped” carapace (top shell) is lightly serrated at the back and is olive to brown or sometimes black in colouration, often with patterns or lines radiating out from a central point on each scute (enlarged scales on the shell). The skin is light brown to dark grey on top and the head, limbs and tail are darker and usually have a yellowish outline. The plastron is white to yellow and the underside of the head, limbs and tail are a mix of white, yellow and dark brown or olive. Males have a longer tail and a large, curved claw on their front flippers that is much larger than the others. Hatchlings have an average carapace length of about 5 cm and are dark green to dark brown, lacking the yellow and light brown colouration found on the adults, and the carapace is keeled.

Similar Species

In Pacific Canada, the Green Sea Turtle may be confused with the Leatherback Sea Turtle. However, the Leatherback Sea Turtle has a leathery shell with longitudinal keels and lacks the bright colouration of the Green Sea Turtle.


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Green Sea Turtles occasionally travel through the waters of Pacific Canada, but they are very uncommon. This species occurs primarily at tropical latitudes in the Atlantic, Pacific and Indian Oceans.


Green Sea Turtles are aquatic and inhabit marine environments. Canadian waters are generally too cold for individuals of this species, which primarily forage in shallow (< 35 m depth), near-shore areas at tropical and sub-tropical latitudes, including the southern United States. Females nest above the high hide tide line on sandy beaches in tropical regions.


Green Sea Turtles can migrate over a thousand kilometres between foraging and nesting grounds, although many individuals forage in areas that are close to their nesting habitat. Females typically reproduce every three years, and they often return to the same beach that they used in previous years. Females lay 1–8 separate clutches of eggs during the nesting season, spaced 9–15 days apart. Nesting typically occurs at night. Females excavate a nest cavity and deposit around 100–120 eggs. The eggs hatch after approximately 2 months, and the hatchlings emerge at night and use light cues to orient toward the ocean. The sex of the offspring is temperature-depend; incubation temperatures of 28°C and lower primarily produce males, temperatures of 30°C and higher produce only females, and intermediate temperatures produce both sexes. Individuals do not reach sexual maturity until they are at least 25 years of age. Maximum lifespan is unknown, but they can likely live for over 60 years. Juvenile Green Sea Turtles are primarily carnivorous and eat a wide variety of small animal prey, such as sponges, corals, jellyfish, bivalves and crustaceans, while adults are largely herbivorous and feed on sea grass and other plants. While foraging, individuals have the remarkable ability to remain below the surface of the water for more than five hours before coming up for air. Like other Sea Turtles, the Green Sea Turtle cannot retract its head or flippers into its shell.


The degradation of near-shore foraging areas and nesting beaches, as well as the harvest of both adults and eggs are likely the most significant threats that have contributed to the extensive global decline of this species. Other threats include by-catch and entanglement in commercial fishing gear, oil spills and other environmental pollution, as well as ingestion of plastic and other marine debris. Climate change may also negatively affect sea turtles in several ways, including increased incidence of nesting beach erosion or shifts in sex ratio resulting from changes to nest incubation temperatures.

Additional Information About This Species In Canada