Loggerhead - Caretta caretta

Taxonomy & Nomenclature

Scientific Name Caretta caretta
Author (Linnaeus, 1758)
Taxonomic Rank Species
Taxonomic # 173830
Common Names English: Loggerhead
Spanish: Tortuga-marina caguama
English: Loggerhead Sea Turtle
Current Standing valid
Taxonomic Parents Kingdom: Animalia
  Phylum: Chordata
    Subphylum: Vertebrata
      Class: Reptilia
        Order: Testudines
          Suborder: Cryptodira
            Superfamily: Chelonioidea
              Family: Cheloniidae
                Subfamily: Carettinae
                  Genus: Caretta
Taxonomic Children
Synonyms (since 1950)
Taxonomic data is courtesy of the Integrated Taxonomic Information System (ITIS)
See ITIS metadata in XML

Physical Description / Field Identification

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.

Distribution

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

Prey species for adults include: Tridacna chametrachae, Tridacna fossor, Lepas sp., Lanthina sp., Vellela sp., Limulus polyphemus, Anadara trapezia, Pinna bicolor, Solen grandis, Stichodactyla haddoni, Portunus pelagicus, Libinia emarginata, Cancer irroratus, Pagurus pollicaris, Ovalipes ocellatus, Mytilus edulis, Busyconsp., Sargassum natans, Ulva sp., Fucus sp., Hippocampus erectus, Virgularia presbytes, Physalia physalis.

Pelagic stage juveniles: Coelenterates > Mollusks > Macroplankton

Prey species for juveniles include: Bittium sp., Cerithium echinatum, Cerithium tenuifilosum, Cymbiolacca pulchra, Cypraea sp., Lophiotoma acuta, Natica gualtieriana, Natica onca, Pupa nitidula, Rhinoclavis apser, Rhinoclavis fasciatum, Rhinoclavis vertagus, Strombus gibberulus, Trochus sp., Turbo bruneus, Turbo perspeciosus, Umbanium vestariius, Fragum fragum, Pinguitellina robusta, Tellina sp., Tridacna maxima, Pleuroncodes planipes, Physalia physalis, Litiopa melanostoma, Diacria trispinosa, Hyperia medusarum, Hyalaea tridentate, Nautilograpsus minututs, Entelurus aequoreus, Janthina sp., Pyrosoma atlanticum, Pterotrachea sp., Idotea metallica, Pelagia noctiluca, Litiopa melanostoma, Velella velella.

Threats and Status

Threats to loggerhead sea turtle include:

• Harvest of eggs/adults

• Ship strikes

• Fisheries bycatch

• Predators at nesting beaches

• Entanglement in debris / fishing gear

• Oil and plastic pollution

All seven species of sea turtles are protected under the United States Endangered Species Act.

Links

References

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.

ITIS TSN173830
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)
#records (spatial)477,684
#records (non-spatial)10
#datasets241
Year1758 - 2017
Latitude-42.37 - 60.77
Longitude-180.00 - 180.00
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