Loggerhead Sea Turtle Facts

Meet the world's largest hard-shelled turtle

Loggerhead Sea Turtle
Loggerhead Sea Turtle. alantobey / Getty Images

The loggerhead sea turtle (Caretta caretta) is a marine sea turtle that gets its common name from its thick head, which resembles a log. Like other sea turtles, the loggerhead has a relatively lengthy life span—the species can live from 47 to 67 years in the wild.

With the exception of the leatherback sea turtle, all sea turtles (including the loggerhead) belong to the family Chelondiidae. Loggerhead turtles sometimes breed and produce fertile hybrids with related species, such as the green sea turtle, hawksbill sea turtle, and Kemp's ridley sea turtle.

Fast Facts: Loggerhead Turtle

  • Scientific Name: Caretta caretta
  • Distinguishing Features: Large sea turtle with yellow skin, reddish shell, and thick head
  • Average Size: 95 cm (35 in) long, weighing 135 kg (298 lb)
  • Diet: Omnivorous
  • Life Span: 47 to 67 years in the wild
  • Habitat: Temperate and tropical oceans worldwide
  • Conservation Status: Vulnerable
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Reptilia
  • Order: Testudines
  • Family: Cheloniidae
  • Fun Fact: The loggerhead turtle is the official state reptile of the state of South Carolina.

Description

The loggerhead sea turtle is the largest hard-shelled turtle in the world. The average adult is about 90 cm (35 in) long and weighs around 135 kg (298 lb). However, large specimens may reach 280 cm (110 in) and 450 kg (1000 lb). Hatchlings are brown or black, while adults have yellow or brown skin and reddish brown shells. Males and females look similar, but mature males have shorter plastrons (lower shells), longer claws, and thicker tails than females. Lachrymal glands behind each eye allow the turtle to excrete excess salt, giving the appearance of tears.

Distribution

Loggerhead turtles enjoy the largest distribution range of any sea turtle. They live in temperature and tropical seas, including the Mediterranean Sea and the Atlantic, Pacific, and Indian Oceans. Loggerheads live in coastal waters and the open sea. The females only come ashore to build nests and lay eggs.

Loggerhead turtle distribution
Loggerhead turtle distribution. NOAA

Diet

Loggerhead turtles are omnivorous, feeding on a variety of invertebrates, fish, algae, plants, and hatchling turtles (including those of its own species). Loggerheads use pointed scales on their forelimbs to manipulate and tear food, which the turtle crushes with powerful jaws. As with other reptiles, a turtle's digestive rate increases as temperature rises. At low temperatures, loggerheads can't digest food.

Predators

Many animals prey upon loggerhead turtles. Adults are eaten by killer whales, seals, and large sharks. Nesting females are hunted by dogs and sometimes humans. Females are also susceptible to mosquitoes and flesh flies. Juveniles are eaten by moray eels, fish, and portunid crabs. Eggs and nestlings are prey to snakes, birds, mammals (including humans), lizards, insects, crabs, and worms.

Over 30 animal species and 37 types of algae live on the backs of loggerhead turtles. These creatures improve the turtles' camouflage, but they have no other benefit to the turtles. In fact, they increase drag, slowing the turtle's swimming speed. Many other parasites and several infectious diseases affect loggerheads. Significant parasites include trematode and nematode worms.

Behavior

Loggerhead sea turtles are most active during the day. They spend up to 85% of the day underwater and can stay submerged for up to 4 hours before surfacing for air. They are territorial, typically conflicting over foraging grounds. Female-female aggression is common, both in the wild and in captivity. While the maximum temperature for the turtles is unknown, they become stunned and start floating when the temperature drops to about 10 °C.

Reproduction

Loggerhead turtles reach sexual maturity between 17 and 33 years of age. Courtship and mating occur in the open ocean along migration routes. Females return to the beach where they themselves hatched in order to lay eggs in the sand. A female lays, on average, about 112 eggs, usually distributed between four clutches. Females only lay eggs every two or three years.

Upon hatching, loggerhead turtles make their way to the sea.
Upon hatching, loggerhead turtles make their way to the sea. ©fitopardo.com / Getty Images

The temperature of the nest determines the sex of the hatchlings. At 30 °C there is an equal ratio of male and females turtles. At higher temperatures, females are favored. At lower temperatures, males are favored. After about 80 days, hatchlings dig themselves out of the nest, usually at night, and head to the brighter surf. Once in the water, loggerhead turtles use magnetite in their brains and Earth's magnetic field for navigation.

Conservation Status

The IUCN Red List classifies the loggerhead turtle as "vulnerable." The size of the population is decreasing. Because of high mortality and slow reproductive rates, the outlook is not good for this species.

Humans directly and indirectly threaten loggerheads and other sea turtles. Although worldwide legislation protects sea turtles, their meat and eggs are consumed where laws aren't enforced. Many turtles die as bycatch or drown from entanglement in fishing lines and nets. Plastic poses a significant threat to loggerheads because the floating bags and sheets resemble jellyfish, a popular prey. Plastic can cause intestinal blockage, plus it releases toxic compounds that damage tissues, thin eggshells, or alter turtle behavior. Habitat destruction from human encroachment deprives turtles of nesting sites. Artificial lighting confuses hatchlings, interfering with their ability to find water. People who find hatchlings may be tempted to help them get to water, but this interference actually lowers their chance of survival, as it prevents them from building the strength needed to swim.

Climate change is another cause for concern. Because temperature determines hatchling sex, rising temperatures may skew gender ratio in favor of females. In this respect, human development may aid turtles, as nests shaded by tall buildings are cooler and produce more males.

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