Loggerhead sea turtle

Loggerheads live in warm and cool seas all around the world.

Baby turtles float far out in the open ocean. Older turtles swim near the coast to find food.

Loggerheads live in the Atlantic, Pacific and Indian Oceans and in the Mediterranean Sea, mostly in warm and mild waters. In the Atlantic they have been seen from Canada all the way to Argentina.

Where a loggerhead lives changes as it grows. Hatchlings and young turtles drift and swim in the open ocean for 7 to 15 years. Then they move to shallower water near the coast, where food lies on the seafloor.

The species occurs in subtropical and temperate parts of the Atlantic, Pacific and Indian Oceans and the Mediterranean Sea; in the western Atlantic it ranges from Newfoundland to Argentina, and in the eastern Pacific it has been reported from Alaska to Chile. Under the United States Endangered Species Act it is managed as nine distinct population segments.

Nesting is concentrated in a few places. NOAA reports that only two nesting groups have more than 10,000 females nesting a year, peninsular Florida and Oman, and that the United States has more than 100,000 nests a year. Smaller nesting groups use beaches in the Caribbean, Cape Verde, Brazil, the eastern Mediterranean, Japan, Australia and New Caledonia.

Loggerheads eat animals with hard shells.

They eat crabs, clams and sea snails. Their strong jaws crunch the shells. Baby turtles eat things that float.

Loggerheads are carnivores, which means they eat other animals. Out in the open ocean, young turtles snack on many kinds of floating food.

Once they move near the coast, they hunt along the seafloor for crabs, horseshoe crabs, clams and big sea snails called whelks and conchs. Their wide heads hold strong jaw muscles that crush those hard shells. Sadly, floating bits of plastic can look like food, and turtles sometimes swallow them.

Loggerheads are carnivorous and only occasionally eat plants. During the oceanic phase they take a wide variety of floating prey, which also exposes them to marine debris: NOAA lists plastic fragments, fishing line, balloons, bags and tar among the items turtles mistake for food.

Juveniles and adults in coastal waters feed mostly on bottom-dwelling invertebrates such as molluscs, crustaceans and horseshoe crabs. The enlarged head houses the jaw muscles that generate the force needed to crush whelks, conchs and crabs.

Loggerheads go on very long swims.

Some cross a whole ocean and come back. Grown-up mothers find their way back to the beach where they hatched.

Loggerheads are amazing navigators. Scientists who fitted turtles with satellite tags found that young loggerheads from Japan and Australia cross the Pacific to feed off Mexico, Peru and Chile, nearly 13,000 kilometers away, and later swim all the way back.

How do they find the way? Experiments with hatchlings from Florida showed they can sense Earth's magnetic field. When scientists recreated the magnetism of different places in the Atlantic, the babies swam in the direction that would keep them on their ocean route.

Satellite tracking has shown trans-Pacific migrations: hatchlings from Japanese and Australian beaches travel nearly 8,000 miles (about 12,900 km) to feed off Baja California, Peru and Chile, spend possibly up to 20 years maturing, then return to the western Pacific to breed.

Laboratory work by Kenneth Lohmann's group at the University of North Carolina found that hatchling loggerheads detect magnetic inclination angle and field intensity. Exposed to fields replicating three widely separated points in the North Atlantic gyre, hatchlings swam in directions that would keep them in the gyre and moving along the route, suggesting they use regional magnetic fields as open-ocean markers from the start.

Loggerheads need our help.

Some get caught in fishing nets by mistake. Beach lights can confuse the babies. People keep beaches dark at night and change their nets to keep turtles safe.

Loggerhead sea turtles are listed as Vulnerable, which means they are at risk. The biggest danger is bycatch, when turtles get caught by accident in fishing nets and on hooks. Boat strikes, plastic, lost nesting beaches and bright beach lights also harm them.

People are helping. Many shrimp nets now have turtle excluder devices, escape hatches that let turtles swim free. People turn off or shield beach lights at night, and nesting beaches are protected and watched.

The IUCN Red List assessed the loggerhead globally as Vulnerable in 2015; under the United States Endangered Species Act five population segments are endangered and four threatened. NOAA identifies bycatch in trawls, longlines and gillnets as the greatest continuing threat, alongside vessel strikes, egg and turtle harvest in some countries, coastal development, artificial lighting, marine debris and rising sand temperatures that can kill eggs or skew sex ratios.

Trends differ by region. Turtle excluder devices, circle hooks and gillnet bans have reduced bycatch in some fisheries, yet the South Pacific population has fallen from an estimated 3,500 nesting females a year in 1977 to about 500, and Oman's large nesting group is declining.