Loggerhead sea turtle

Photograph by Joel Sartore, National Geographic Photo Ark
Read Caption

A juvenile loggerhead sea turtle photographed at Newport Aquarium in Kentucky.

Photograph by Joel Sartore, National Geographic Photo Ark

What is the loggerhead sea turtle?

The largest of all hard-shelled turtles, loggerheads are named for their massive heads and strong jaws (leatherbacks are bigger but have soft shells). Their reddish-brown shell, or carapace, is heart-shaped. Their front flippers propel them through the water like wings, and their hind feet stabilize and steer them. While adults males generally weigh about 250 pounds, loggerheads of more than a thousand pounds have been found.

The Loggerhead is considered a “keystone species,” meaning that other animals in its ecosystem depend on it for survival. These turtles feed on invertebrates, whose shells pass through their digestive systems and, upon excretion, fall back to the bottom of the ocean for other animals to eat as a calcium source. Predators also rely on loggerhead hatchlings for food, while more than a hundred species of animals—including barnacles, crabs, and algae—live on their shells.

Habitat

These highly migratory turtles have an enormous range that encompasses all but the most frigid waters of the world’s oceans. They prefer coastal habitats in temperate and subtropical regions, though they often frequent inland water bodies and will travel hundreds of miles to reach them.

Reproduction

Mature loggerhead females often return to the beach where they hatched to lay their own eggs, sometimes traveling thousands of miles. They’re able to do so with the help of Earth’s invisible magnetic field, which loggerheads use to navigate at sea. Each stretch of coastline has its own magnetic signature, and these turtles remember and use them as guides.

Breeding occurs year-round but peaks in the summer months. Females may lay two to five clutches of up to 130 eggs in a season with different mates.

Diet

Loggerhead sea turtles are primarily carnivores, and their strong jaws allow them to crush conchs, bivalves, and horseshoe crabs. They also eat jellyfish, shrimp, sponges, fish, and sometimes even seaweed and sargassum.

Threats to survival

Loggerheads are the most common of all the sea turtle species in waters the waters of the United States. But persistent population declines due to pollution, shrimp trawling, and development in their nesting areas, among other factors, have kept this wide-ranging seagoer listed as threatened under the U.S. Endangered Species Act since 1978.

Fisheries pose the greatest threat to the loggerhead turtle, which often gets caught accidentally in fishing gear like trawls and nets. Humans also have killed these turtles for their meat and skin for years, while ocean debris can injure or kill them.

Climate change is also throwing off the ratio of male and female sea turtles. The temperature of the sand in which turtles are hatched determines their sex—and, as those temperatures rise, more female loggerheads are being born. Climate change is also raising sea levels and creating more extreme weather events, which also harm the turtle’s coastal habitat.

Conservation

There are efforts underway around the world to save the loggerhead sea turtle. In the southeastern U.S., communities are working to protect the turtle’s beach habitats and nesting areas. Some communities have developed ordinances reducing the amount of artificial light allowed near nesting sites as it can disorient hatchlings making their way from the nest to the sea.

Since 1987, the U.S. has required commercial fisheries to use turtle excluder devices that help turtles escape from fishing nets. When these devices are fitted into the neck of a trawl net, larger animals like turtles bounce off their grid-like bars while smaller animals like shrimp pass through.

In spite of these protections, loggerhead sea turtle populations continue to decrease. Given the migratory nature of these animals, researchers say that long-term international cooperation is essential to their stability.

Crowd Cheers as Sea Turtles Return to the Sea Watch sea turtles return to the ocean after being rehabilitated at a rescue center in North Carolina.