Blackbeard Island National Wildlife Refuge
Southeast Region
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Loggerhead Sea Turtle -- (Caretta caretta)

Loggerhead sea turtle hatchling trekking across the beach. Credit: USFWS

Loggerhead sea turtle hatchling trekking across the beach. Credit: USFWS

The loggerhead sea turtle is one of five sea turtles living in Georgia waters and the only one to regularly nest there.  Reportedly attaining a maximum weight of 800 lbs. and a carapace (back shell) length of 42 inches, the loggerhead may be the largest living hard-shelled turtle.  Most nesting females in Georgia weigh 250-400 lbs. and have carapaces that are about 36 inches long.

Loggerheads are truly marine animals, never coming out of the sea except to nest.  Like most turtles, they lay leathery-shelled eggs on land, bury them, and leave them unattended.  There is no parental care of the young among living turtles. Most Georgia loggerheads lay about 120 golfball-sized eggs per nest, and many nest as often as five times in a given season (May through August in our area).  However, loggerheads nesting in Georgia lay eggs every two or three years, not every year, and the two-year cycle is most common. Male loggerheads never return to land once they enter the sea as hatchlings.

Loggerhead eggs take about two months to develop.  Cool weather prolongs the incubation period; warm weather shortens it. Researchers discovered several years ago that temperature even determines the sex of the developing sea turtle embryo.  Sea turtles lack sex chromosomes:  in general, an embryo developing under warmer conditions becomes a female; cooler conditions produce males.

Baby loggerheads hatch out one or more days prior to emerging from their nest.  The constant movement of the hatchlings pushes their massed bodies further toward the top of the nest and finally, to the point where they can feel the surface temperature.  When the temperature drops (usually an hour or two after sundown), the uppermost turtles become active, initiating a chain reaction of motion that propels the mass of the hatchlings up and out of the nest cavity.  One hundred sea turtles can exit a nest in less than three minutes, allowing them time to orient visually toward the ocean and begin the trek down the beach before nocturnal predators are alerted.  Upon entering the surf, they change their gait from a slow plod to a powerful swimming stroke that will propel them under breaking waves and offshore.  Under laboratory conditions, they swim constantly for several days.  This presumably carries the hatchlings out into the ocean currents that transport them to their nursery grounds.  Exactly

Adult female loggerhead returning to sea after laying her eggs. Credit: USFWS

Adult female loggerhead returning to sea after laying her eggs. Credit: USFWS

where these nursery grounds are remains a perplexing mystery.  Current theory holds that baby sea turtles spend their first few years floating in mats of seaweed.  Caught up in eddies and gyres of the Gulf Stream, these young turtles may travel across the Atlantic and back before they begin showing up in tidal creeks when they reach 2 feet in lenght at 3-5 years of age.

Major predators of loggerhead nests are raccoons, ghost crabs, humans and feral pigs.  Hatchlings are eaten by raccoons, ghost crabs, a variety of gulls and other birds, and a host of fishes.  Adult turtles fall prey to large sharks and are killed by motorboats.

Because of increased loss of habitat and evidence of declining populations, the loggerhead sea turtle was placed on the Threatened Species List in 1978 and is protected by federal law.

 

Last updated: April 17, 2009