Flatback Sea Turtle

Natator depressus

Scientific Classification

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

Species Description

Adult Weight: Up to 90 kgs (200 lbs)
Adult Size: 1 m (3.25 ft)
Appearance:  Olive greenish carapace with flat contour
Diet: Jellyfish, sea cucumbers and other soft-bodied invertebrates

Natural Lifespan: 100 years
Age at Sexual Maturity: 7 - 50 years
Average Clutch Size: 50 - 70 eggs
Average Clutches per Season: 2 - 3 clutches
Nest Incubation Period: 55 - 60 days 
Remigration Interval: 1.6 - 2.2 years

Life Cycle


Geographic Range: Subtropical coastal zones on the north, northeast and northwest fringes of Australia stretching up to the waters off southern Papua New Guinea.

Marine Habitat Use: Flatbacks nest solely on the coast of Australia.

Hatchlings appear to remain in and prefer silty, nearshore waters instead of dispersing out into the open ocean. Adults primarily inhabit coastal waters, with the exception of venturing to Papua New Guinea to forage.


Scientists considered flatbacks to be a subspecies of green turtle until the species received separate recognition in 1988. Flatbacks are the only population of sea turtles listed as data deficient by the IUCN. Further research is needed to identify specific threats to flatbacks, determine the status of the species and develop species-specific conservation priorities. Flatback nesting beaches are monitored, but flatbacks are captured as fisheries bycatch.

Fun Fact

Saltwater crocodiles prey on flatbacks (Crikey!)