Flatback Sea Turtle Facts, Pictures & In-Depth Information For Kids & Adults

Flatback sea turtle facts, pictures and information. This page is part of our sea turtles series.

fatback sea turtle facts
Photo by Lyndie Malan [CC BY-SA 3.0]

Flatback Sea Turtle Facts At A Glance

  • Other Name(s): Australian flatback sea turtle, flatback turtle
  • Scientific name: Natator depressus
  • Type of Animal: Reptile, Sea Turtle
  • Animal Family: Cheloniidae
  • Where Found: Coastal waters of Australia, Indonesia and New Guinea
  • Length: carapace (shell) length 80 - 96 cm (31 - 38 in.)
  • Weight: 70 - 90 kg (154 - 198 lb.)
  • Conservation Status: Data Deficient
  • Other interesting flatback Sea Turtle facts: The flatback sea turtle doesn’t migrate and has the smallest range of all sea turtles. It nests only on the northern coastline of Australia.

Meet The Flatback Sea Turtle: Introduction

The flatback turtle is a large marine reptile, and one of the 7 species of sea turtle living today. It has a hard shell, and its limbs have adapted into flippers, with which it propels itself through the water.

The flatback turtle is so-called because of the distinctive flat shape of its carapace (upper shell). Unlike other sea turtles, the flatback turtle does not migrate long distances. It nests only on the beaches of northern Australia, and is only found off the coasts of Australia and New Guinea.

You can see some excellent footage of hatchling flatback sea turtles in the video below:

Now let's find out more about this amazing reptile ...

What Does The Flatback Sea Turtle Look Like?

The flatback sea turtle is a mid-sized sea turtle. It has an average length of around 90 cm (35.5 in.), and weight of 73 kg (161 lb.). It is larger than the olive and Kemp’s ridley turtles, but not as large as the green, loggerhead or leatherback turtles.

The flatback sea turtle is recognizable by the shape of its carapace (upper shell). The carapace is flatter, and not as steeply-domed, as that of other sea turtles. Around the outer edges the shell becomes flat or even slightly upturned.

The turtle’s carapace is grey, olive green or brown in color. The scutes (the large plates) of the flatback’s carapace do not overlap. The underside of the shell (the plastron) is pale yellow-white.

The flatback sea turtle’s limbs and head are grey / olive green.

The flatback turtle’s carapace is thinner than that of the other hard-shelled sea turtles. Because of this it is susceptible to cracks or other damage.

The Largest Hatchlings Of Any Sea Turtle

By Purpleturtle57 (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons
Flatback sea turtle hatchlings are the largest of any sea turtle. Photo by Purpleturtle57 [CC BY-SA 3.0]
Flatback sea turtle hatchlings are the largest of any sea turtle. They have a carapace length of around 6 cm (2.36 in.), and weigh around 43 g (1.5 oz.). Their shells are olive-green in color, with yellow rims and black in between the individual scutes.

Their large size means that flatback hatchlings are better protected against predators, and more powerful swimmers, than the young of other sea turtle species.

Flatback Sea Turtle Family & Related Animals

The flatback sea turtle is one of the six sea turtles that make up the family Cheloniidae.

The only living sea turtle not in this family is the leatherback turtle, which is on its own in the family Dermochelyidae.

The seven living species of sea turtle are part of the order Testudines. This group of animals includes all turtles, tortoises and terrapins. The members of this group all have shells, lay eggs, and are ectothermic (cold-blooded).

Being ectothermic means that the turtle has no means of altering its own body temperature. By comparison, endothermic (warm-blooded) animals such as humans can regulate body temperature by (for example) shivering.

The Testudines have been around for 220 million years. They appeared before snakes and crocodilians, and make humans (who have been around for around 200,000 to 300,000 years) seem positively young!

Where Do Flatback Sea Turtles Live?

Unlike the other sea turtles, the flatback turtle does not undertake long migrations. The species has a smaller range (the area in which it is found) than any other sea turtle.

The flatback sea turtle is primarily found in the coastal waters of Australia (from the East coast of Queensland to the west coast of Western Australia). It is also found off the coasts of Papua New Guinea and Indonesia.

Where Do Flatback Sea Turtles Nest?

The flatback sea turtle only nests on the north coast of Australia. Nesting sites are located both on the mainland and on the coastlines of offshore islands. Some of the most popular nesting sites are found in the north-east of the Gulf of Carpentaria and the western Torres Strait.

You can see these locations on the map below:

Flatback Sea Turtle Habitat

The flatback sea turtle lives by the coast in shallow, tropical and subtropical waters. It is found in soft-bottomed areas, usually away from reefs.

What Does The Flatback Sea Turtle Eat?

The flatback turtle is omnivorous (i.e. it eats both plants and meat). It forages on the sea bed and invertebrates make up the bulk of its diet. The turtle eats animals such as corals, sea cucumbers, shrimp, jellyfish and mollusks.

Although plants form only a minor part of the flatback sea turtle’s diet, the species will occasionally eat sea grasses.

Flatback Sea Turtle Life Cycle

Like all sea turtles, the flatback turtle is oviparous (an egg-laying species). Mating takes place in the sea. Female flatback turtles then haul themselves out of the ocean using their flippers. They excavate nests in the sand, into which they lay their eggs.

Flatback sea turtles nest at different times of the year depending on the location of the nesting sites. Around the Gulf of Carpentaria they are known to nest all year round, with nesting peaking from June to August. In southern Queensland, nesting occurs from November to January, and is at its peak from late November to early December.

The female turtles build their nests high up on sandy beaches. The nest consists of a hole around 22 cm (9 in.) in diameter and 30 cm (1 ft.) deep.

Into this hole the female will lay an average of 50 eggs. The flatback’s clutch (the eggs laid in one nest) is smaller than that of other sea turtle species, which may be as large as 200 eggs.

After covering up the eggs and filling the hole with sand, the female will make her way back to the ocean. Nesting usually takes place at night.

As with other sea turtles (and other reptiles) the temperature of the nest determines the sex of the hatchlings. If the nest is below 29°C then the hatchlings will be male. If the nest is above that temperature then the hatchlings will be female.

The eggs, which are larger than those of all other sea turtles, hatch after a period of around 6 weeks. The hatchlings make their way instinctively towards the sea.

Flatback hatchlings are larger than those of other sea turtles. This offers them some protection, but they are still vulnerable while out of the water. A large number of predators, including foxes, wild pigs and birds, prey on the hatchlings at this time.

Whereas other sea turtle hatchlings drift in the open ocean for the first few years of their lives, flatback hatchlings remain close to the shore.

Female flatbacks are able to breed at around 20 years of age, and nest every 2 to 3 years.

Flatback Sea Turtle Predators & Parasites

Adult flatback turtles are large and well-protected. Although the risk of predation is relatively low, they are still at risk from sharks. Nesting adult females are at risk from predation by saltwater crocodiles.

Predators of hatchling flatback sea turtles include: sand monitor lizards, dingoes, foxes, wild pigs, crabs, birds such as gulls, night herons and pelicans, and fish.

Flatback Sea Turtle Conservation Status

The flatback sea turtle is the least studied sea turtle, and its IUCN conservation status is ‘Data Deficient’. However, the species is listed as Vulnerable under the Western Australia Biodiversity Conservation Act 2016 and the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.

Threats to the flatback sea turtle include: the loss or development of nesting sites; habitat loss due to coastal development; entanglement in fishing nets; and light pollution that confuses hatchlings making their way to the water.

One of the biggest threats to the flatback sea turtle comes from egg collection by indigenous people.

Flatback Sea Turtle Facts: Related Articles

Discover other sea turtle species:

See pictures and facts about amazing animals from all around the world here: A to Z Animals

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