Cheloniidae in the context of "Hawksbill sea turtle"

Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerhead, Kemp's ridley, and olive ridley. 5 of the seven species are listed as threatened with extinction globally on the IUCN Red List of Threatened Species, the remaining two are not considered to be threatened with extinction. One of which, the flatback turtle, is found only in the waters of Australia, Papua New Guinea, and Indonesia.

Sea turtles can be categorized as hard-shelled (cheloniid) or leathery-shelled (dermochelyid). The only dermochelyid species of sea turtle is the leatherback.

The loggerhead sea turtle (Caretta caretta) is a species of oceanic turtle distributed throughout the world. It is a marine reptile, belonging to the family Cheloniidae. The average loggerhead measures around 90 cm (35 in) in carapace length when fully grown. The adult loggerhead sea turtle weighs approximately 135 kg (298 lb), with the largest specimens weighing about 200 kg (440 lb). The skin ranges from yellow to brown in color, and the shell is typically reddish brown. No external differences in sex are seen until the turtle becomes an adult, the most obvious difference being the adult males have thicker tails and shorter plastrons (lower shells) than the females.

The loggerhead sea turtle is found in the Atlantic, Pacific, and Indian Oceans, as well as the Mediterranean Sea. It spends most of its life in saltwater and estuarine habitats, with females briefly coming ashore to lay eggs. The loggerhead sea turtle has a low reproductive rate; females lay an average of four egg clutches and then become quiescent, producing no eggs for two to three years. The loggerhead reaches sexual maturity within 17–33 years and has a lifespan of 47–67 years.

The green sea turtle (Chelonia mydas), also known as the green turtle, black sea turtle, and Pacific green turtle, is a species of large sea turtle of the family Cheloniidae. It is the only species in the genus Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans, but it is also found in the Indian Ocean. The common name refers to the usually green fat found beneath its carapace, due to its diet strictly being seagrass, not to the color of its carapace, which is olive to black.

The dorsoventrally flattened body of C. mydas is covered by a large, teardrop-shaped carapace; it has a pair of large, paddle-like flippers. It is usually lightly colored, although in the eastern Pacific populations, parts of the carapace can be almost black. Unlike other members of its family, such as the hawksbill sea turtle, C. mydas is mostly herbivorous. The adults usually inhabit shallow lagoons, feeding mostly on various species of seagrasses. The green sea turtle is the only aquatic turtle species which is herbivorous when fully grown.

The Australian flatback sea turtle (Natator depressus) is a species of sea turtle in the family Cheloniidae. The species is endemic to the sandy beaches and shallow coastal waters of the Australian continental shelf. This turtle gets its common name from the fact that its shell has a flattened, lower dome than the other sea turtles. It can be olive green to grey with a cream underside. It averages from 76 to 96 cm (30 to 38 in) in carapace length and can weigh from 70 to 90 kg (150 to 200 lb). The hatchlings are larger than other sea turtle hatchlings when they hatch and emerge from their nests.

The flatback turtle is listed by the IUCN Red List of Threatened Species as data deficient, meaning there is insufficient scientific information to determine its conservation status at this time. It was previously listed as vulnerable in 1994. It is not as threatened as other sea turtles due to its small dispersal range. This animal can be 31 to 37 inches long and about 100 kg in weight.

Kemp's ridley sea turtle (Lepidochelys kempii), also called commonly the Atlantic ridley sea turtle, Kemp's ridley turtle, and Kemp's ridley, is a species of turtle in the family Cheloniidae. L. kempii is the rarest species of sea turtle and is the world's most endangered species of sea turtle as well as the smallest. It is one of two living species in the genus Lepidochelys (the other one being L. olivacea, the olive ridley sea turtle). The species L. kempii primarily occupies habitat around the Gulf of Mexico, though its migrations into the Atlantic Ocean are being affected by rising temperatures. Rising sea temperatures expand this species range, leaving them vulnerable to cold-shocking events when weather changes. Kemp's ridley sea turtle is listed as endangered under the Endangered Species Act (ESA), and conservation efforts are attempting to rebuild population numbers. Human activity, including habitat destruction, climate change, and oil spills, threaten populations.

The olive ridley sea turtle (Lepidochelys olivacea), also known commonly as the Pacific ridley sea turtle, is a species of turtle in the family Cheloniidae. The species is the second-smallest and most abundant of all sea turtles found in the world. L. olivacea is found in warm and tropical waters, primarily in the Pacific and Indian Oceans, but also in the warm waters of the Atlantic Ocean.

This turtle and the related Kemp's ridley sea turtle are best known for their unique synchronised mass nestings called arribadas, where thousands of females come together on the same beach to lay eggs.