A flatback turtle is a sea turtle native to the northern coast of Australia and nearby waters. The scientific name for the species is Natator depressus, and it is also sometimes called the Australian flatback. Both the scientific and common names refer to the turtle's most obvious characteristic, the shape of its shell, which has a very flat top. The flatback turtle breeds only in certain areas of Australia, is considered endangered.
An adult flatback turtle weighs from 184 to 275 pounds (84 to 125 kg) and grows to about 3.25 feet (1 m) long. The turtles' shells are olive gray on the top and bottom with yellow sections on each side. The shells are unusually thin and have upturned edges. Hatchling flatback turtles have olive gray shells with a distinctive dark gray edge around the edge of each section.
These sea turtles are found only in the coastal waters of Australia, from the northwestern to northeastern regions, and the nearby coasts of New Guinea and Indonesia. Flatbacks prefer muddy, clouded water close to shore, unlike the majority of sea turtles who choose to live in clear waters farther from shore. They are often found in shallow, turbid, bays and estuaries, or grassy shallows.
Their food sources are all in the ocean and consist primarily of soft-bodied marine animals. The most common items in their diet are jellyfish, soft corals, squid and sea cucumbers. They apparently also eat prawns, seaweed and some mollusks.
November and December are the flatback turtle's breeding season and they nest only on the north-northeast coast of Australia and nearby islands. They prefer muddy sloping beaches with a fairly steep pitch for nesting sites. The clutches average about 50 eggs each, which is fewer eggs per clutch than most sea turtles lay, and the eggs are larger than those of other sea turtles. Flatback turtle babies emerge in 47 to 58 days, are large compared with other sea turtle hatchlings, and mature more quickly than most. Each female flatback turtle can lay three to four clutches per year.
Flatback turtles are hunted by salt water crocodiles, and hatchlings are attacked by a number of predators including dingoes, foxes, sea eagles, herons and rats. Other threats to the species include being becoming tangled in fishing lines or nets, the illegal collection of eggs, and disruption of their limited habitat. The species is protected from hunting or collection by both state and national Australian laws.