Loggerhead Sea Turtle (Caretta caretta): Facts and Habitat

What does a loggerhead sea turtle look like?

The loggerhead’s most obvious feature is its head. It is wide and blocky, much bigger in proportion than the head of a green or hawksbill turtle, and it is packed with jaw muscles. The upper shell, or carapace, is slightly heart-shaped and reddish brown, and it is often encrusted with barnacles, algae and other hitchhikers. The lower shell, or plastron, is pale yellow.

The skin on the head, neck and flippers is reddish brown to brown on top and yellowish on the sides and underneath. Each front flipper normally carries two claws. Like all sea turtles, a loggerhead cannot pull its head or flippers into its shell, which is one of the key differences between sea turtles and land tortoises (see turtle vs tortoise).

A few details help with identification. The carapace usually has five pairs of large side plates, called costal scutes, while green and hawksbill turtles have four pairs. Hatchlings are dark brown to almost black, with paler edges on the flippers, and they lack the warm reddish tones of adults.

Males and females look the same until they mature. Adult males then grow a much longer, thicker tail that extends well beyond the shell, longer curved claws on the front flippers and a slightly shorter plastron.

How big do loggerhead turtles get?

The loggerhead is one of the largest hard-shelled turtles. NOAA Fisheries gives a typical adult shell length of about 76–107 cm (2.5–3.5 ft) and an adult weight of about 91–159 kg (200–350 lb). Nesting females measured on beaches around the world range from roughly 70 cm to just over 1 m (28–43 in) in straight shell length.

Size varies between populations. Mediterranean loggerheads are the smallest in the world on average, while turtles nesting in the southeastern United States and Oman are larger. Claims of loggerheads weighing several hundred kilograms more than this come from old, unverified reports and should be treated with caution.

Where do loggerhead turtles live?

Loggerheads have one of the widest ranges of any sea turtle and nest over a broader band of latitudes than any other species. They live in the Atlantic, Pacific and Indian oceans and throughout the Mediterranean Sea, mostly in temperate and subtropical waters rather than the deep tropics. In the western Atlantic, they range from Newfoundland in Canada to Argentina, and in the eastern Pacific they have been reported from Alaska to Chile.

Their habitat changes with age. Hatchlings swim straight out to sea and spend roughly 7–15 years drifting and feeding in the open ocean, often among floating mats of Sargassum seaweed. Larger juveniles then move to coastal waters such as bays, lagoons, estuaries and the continental shelf, where adults also feed. Loggerheads usually live in water of about 13–28 °C (56–82 °F) and migrate to warmer areas when the sea cools.

Loggerheads are the most common sea turtle in US coastal waters. In Europe they are regular in the Mediterranean and around the Azores, Madeira and the Canary Islands, and storm-blown juveniles occasionally strand on the coasts of Ireland and Britain.

What do loggerhead turtles eat?

The loggerhead is mainly a carnivore and has the broadest known diet of any sea turtle. Its heavy jaws are built for hard prey: adults feed on the seabed on whelks, conchs, clams, crabs, horseshoe crabs, sea urchins and other invertebrates, cracking shells that most predators cannot open. They also eat sponges, sea pens, worms, squid and fish, and occasionally a little seaweed.

Young loggerheads in the open ocean eat what floats near the surface: jellyfish, small crustaceans, snails, fish eggs and insects blown out to sea. Unfortunately, they also swallow plastic fragments that collect in the same drift lines as their food. For a comparison with other species, see what do sea turtles eat?

Behavior and migration

Loggerheads are mostly solitary and active by day. They spend most of their time underwater and come up only to breathe. Typical dives last about 15–30 minutes, but resting turtles in cool water can stay down for several hours, because their slow metabolism needs little oxygen. Females can be surprisingly aggressive toward each other on feeding grounds, circling, sparring and snapping at each other’s jaws over the best spots.

Loggerheads are champion travelers. Hatchlings from Florida ride the North Atlantic Gyre, a huge loop of ocean currents, toward the Azores and back, a circuit of many thousands of kilometers. In the Pacific, loggerheads hatched in Japan cross the ocean to feed off Baja California, Mexico, and later return to Japan to breed. In 1996, a female named Adelita became the first animal tracked by satellite across an entire ocean basin, swimming more than 11,000 km (7,000 mi) from Mexico to Japan.

They find their way with a built-in sense of Earth’s magnetic field, which works both as a compass and as a kind of map. Learn how this works in how do sea turtles navigate?

Nesting and life cycle

Loggerheads mature slowly. Depending on the population, females first breed at roughly 20–35 years of age, and NOAA puts the typical age at maturity in the US at about 35 years. Adults migrate hundreds to thousands of kilometers to breed in the general region where they hatched, usually every 2–3 years. In the Northern Hemisphere they mate from late March to early June, and females nest from about late April to early September.

A female crawls ashore at night, digs a body pit and then an egg chamber with her back flippers, and lays about 100–120 eggs the size of ping-pong balls. She covers the nest and returns to the sea, and the whole process takes about one to two hours. She nests three to five times in a season, roughly two weeks apart. The world’s biggest nesting populations are in Florida and Oman; read more in where do loggerhead turtles nest?

The eggs incubate in the sand for about two months. As in other sea turtles, the temperature of the nest decides the sex of the hatchlings: cooler sand produces males and warmer sand produces females, with roughly equal numbers at about 29–30 °C (84–86 °F). Hatchlings dig out together, usually at night, and scramble toward the brightest horizon, which on a natural beach is the sea.

Only a small fraction survive to adulthood. Crabs, birds, raccoons, foxes and fish take many eggs and young, and the rest face years in the open ocean. See how many baby sea turtles survive?

How long do loggerheads live?

Nobody knows exactly, because wild turtles outlive the researchers and tags that follow them. Estimates based on growth rings in bones and long-term tagging suggest a lifespan of roughly 50–70 years, and NOAA says loggerheads may live 80 years or more. Because they take decades to mature and keep breeding for many years afterward, long-lived adults are especially important to every population.

Predators and threats

Eggs and hatchlings have many natural predators, including ghost crabs, raccoons, foxes, coyotes, wild pigs, gulls, frigatebirds and many fish. On some Florida beaches, raccoons once destroyed nearly every nest in a season until nests were protected with wire screens. Introduced red foxes caused similar losses in eastern Australia. Adults have few enemies, but large sharks such as tiger sharks, as well as killer whales, can kill them.

People are the main threat today. NOAA lists bycatch, the accidental capture of turtles in trawls, longlines, gillnets and other fishing gear, as the greatest continuing threat worldwide. Other problems include coastal development and seawalls that remove nesting beaches, beachfront lights that lead hatchlings and females away from the sea, collisions with boats, plastic and other debris, illegal taking of eggs and meat in some countries, and climate change, which can flood nests and turn warming beaches into female-only nurseries.

Conservation status

The IUCN Red List classifies the loggerhead as Vulnerable worldwide, based on its latest global assessment in 2015. The picture is very different between regions. The Mediterranean population, for example, is assessed as Least Concern and its nest counts are increasing, while the population nesting in the South Pacific fell from about 3,500 females a year in 1977 to around 500 today, according to NOAA.

In the United States, loggerheads have been protected under the Endangered Species Act since 1978, and since 2011 the species has been managed as nine distinct population segments, five listed as endangered and four as threatened. International commercial trade is banned under Appendix I of CITES. Turtle excluder devices, escape hatches fitted to shrimp trawls, have been required in US shrimp fisheries since the late 1980s and early 1990s and let most trapped turtles swim free. Nest protection, beach lighting rules and long-term monitoring have helped stabilize several key populations.

Myths and facts

Myth: Loggerheads cry when they lay eggs. Nesting females often appear to shed tears, but they are not sad or in pain. Like other sea turtles, loggerheads have salt glands behind the eyes that remove excess salt from the seawater they swallow, and on land the salty fluid runs down the face.

Myth: Sea turtles can hide in their shells. Unlike many freshwater turtles, loggerheads cannot retract their head or flippers. Their streamlined shell is built for swimming, not hiding.

Fact: A loggerhead is a moving reef. Scientists have recorded more than 100 kinds of animals and dozens of kinds of algae living on loggerhead shells, from barnacles and crabs to tiny worms.

Fact: Loggerheads can hybridize. Genetic studies show that loggerheads occasionally interbreed with other sea turtles, including the hawksbill, Kemp’s ridley and green sea turtle, particularly off the coast of Brazil.

Loggerheads and people

Loggerheads are among the most visible sea turtles for visitors to Florida, the Carolinas, Greece, Turkey and Cyprus, where nesting beaches attract tourists every summer. In many of these places, volunteers patrol beaches at dawn, mark nests and help monitor hatching. Responsible viewing means staying off marked nests, keeping beaches dark at night, filling in holes and removing beach furniture, never touching turtles or hatchlings, and joining guided turtle walks where they are offered. In the water, divers and snorkelers should keep their distance and let the turtle choose its own path.