As adults and subadults, Caretta caretta have reddish-brown carapaces (upper shells) with dull brown to yellowish plastrons (lower shells). Hatchlings are brown. Loggerhead turtles have large heads, and their carapace is covered by horny scutes (hard scales that cover the shell). Loggerhead sea turtles have 5 pairs of costals (large scutes running down each side of the carapace), 11 or 12 pairs of marginals (small scutes along the outer edge of the carapace), and five vertebrals (large scutes stretching down the center of the carapace). Adults weigh up to 160 kg (mean 113 kg) with a carapace length of 82 to 105 cm. Hatchling Caretta caretta weigh about 20 g and are about 45 mm long.
Can be Confused With
Small Caretta caretta may be confused with Kemp’s Ridley (Lepidochelys kempii) turtles in the Gulf of Mexico or along the west Atlantic coast. Loggerhead turtles can be distinguished from Kemp’s ridleys by their larger size and brown color. Loggerhead turtles can be distinguished from the green turtle (Chelonia mydas) by the former’s thick horny scutes and pointier head.
Loggerhead sea turtles are distributed throughout global sub-tropical and temperate waters, primarily on continental shelves and in estuaries. They exist in highly separate populations (Antitropical and Vicariant distribution) in the northern Indian Ocean, southwestern Indian Ocean, eastern Australia, Japan, southeastern United States, the Mediterranean, and southern Brazil.
Nesting is concentrated in the temperate zone and subtropics, while avoiding tropical beaches. The largest known nesting group was reported in Oman, while another large nesting aggregation has been recorded on the Caribbean coast of Mexico. A large number of nests are also found along the Atlantic coast of Florida, with nests occurring along the coast up to North Carolina.
Ecology and Behavior
Hatchling loggerhead turtles leave the beach on which their mother nested and swim directly offshore, associating with sargassum (seaweed) mats and debris in the open ocean for several years (until they are 40 to 50 cm straight carapace length). Then as subadults, loggerheads will move into the continental shelf region to forage on benthic (bottom-dwelling) organisms like crabs and shellfish. Loggerheads become sexually mature at approximately 30 to 40 years old. After reaching reproductive maturity, male and female turtles will congregate in waters off of nesting beaches, where courtship and mating take place from May to early June. Females will climb up the beach at night, dig a nest, and then lay her clutch (group) of eggs, and re-cover the nest with sand. A female loggerhead may lay multiple clutches of eggs (approximately 100 to 125 eggs per clutch) through the nesting season, usually from May until early September in the northern hemisphere. A female loggerhead may nest between 1 and 7 times per season (mean = 4.1 nests/season), and will migrate to the nesting beach for reproduction every two to three years, on average. Hatchlings incubate for a period of approximately 2 months before emerging; both incubation period length and the sex ratio of hatchlings are determined by the temperature of the nest.
Feeding and Prey
Loggerhead sea turtles eat a wide variety of prey items, including invertebrates from at least eight phyla. Occupying coastal waters, they feed primarily on shellfish and crabs on the seafloor, but also scavenge fish or fish parts as available (e.g., from fisheries discards). Pelagic stage loggerheads feed on the assemblage of species found with sargassum rafts, especially coelenterates and gastropods.
Subadult/Adult: Mollusks > crustaceans > other invertebrates
Caribbean Conservation Corporation/Sea Turtle Survival League. Accessed 2011. Species fact sheet: Loggerhead sea turtle. Available online here.
Lutz, P.L and J.A. Musick, eds. 1997. The Biology of Sea Turtles. CRC Press LLC, New York, NY.
National Marine Fisheries Service and U.S. Fish and Wildlife Service. 1991. Recovery plan for U.S. population of loggerhead turtle. National Marine Fisheries Service, Washington, DC.
National Marine Fisheries Service and U.S. Fish and Wildlife Service. 1998. Recovery plan for U.S. Pacific populations of the loggerhead turtle (Caretta caretta). National Marine Fisheries Service, Silver Spring, MD.
National Research Council. 1990. Decline of the sea turtles: Causes and prevention. National Academy Press, Washington, DC.
Status - ESA, U.S. FWS -
T (Southeast Indo-Pacific Ocean) E (Mediterranean Sea) E (Northeast Atlantic Ocean) E (North Pacific Ocean) T (Northwest Atlantic Ocean) E (North Indian Ocean) E (South Pacific Ocean) T (Southwest Indian Ocean) T (South Atlantic Ocean)
Status - Red List, IUCN -
CR (North East Indian Ocean) CR (South Pacific) CR (North West Indian Ocean) EN (North East Atlantic) LC (South West Atlantic) LC (North West Atlantic) LC (North Pacific) LC (Mediterranean) NT (South West Indian Ocean) NT (South East Indian Ocean) VU (Global or one of the sub regions)