The loggerhead sea turtle appeared about 40 million years ago

The loggerhead sea turtle appeared about 40 million years ago - Culture's Ways

 The loggerhead sea turtle, or loggerhead, is an oceanic turtle distributed throughout the world. It is a marine reptile, belonging to the family Cheloniidae.

 

What is the loggerhead sea turtle?

The average loggerhead measures around 90 cm (35 in) long when fully grown, although larger specimens of up to 280 cm (110 in) have been discovered. The adult loggerhead sea turtle weighs approximately 135 kg (298 lb), with the largest specimens weighing in at more than 450 kg (1,000 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 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 loggerhead sea turtle is omnivorous, feeding mainly on bottom-dwelling invertebrates. Its large and powerful jaws serve as an effective tool for dismantling its prey. Young loggerheads are exploited by numerous predators; the eggs are especially vulnerable to terrestrial organisms. Once the turtles reach adulthood, their formidable size limits predation to large marine animals, such as sharks.

Loggerheads are considered an endangered species and are protected by the International Union for the Conservation of Nature. Untended fishing gear is responsible for many loggerhead deaths. Turtles may also suffocate if they are trapped in fishing trawls. Turtle excluder devices have been implemented in efforts to reduce mortality by providing an escape route for the turtles. Loss of suitable nesting beaches and the introduction of exotic predators have also taken a toll on loggerhead populations. Efforts to restore their numbers will require international cooperation, since the turtles roam vast areas of ocean and critical nesting beaches are scattered across several countries.

Loggerhead turtles, along with green sea turtles, are the sea turtle species that are most commonly kept in captivity. Adults have an average weight range of 80 to 200 kg (180 to 440 lb) and a length range of 70 to 95 cm (28 to 37 in). The maximum reported weight is 545 kg (1,202 lb) and the maximum carapace length is 213 cm (84 in).

Evolutionary history

Although evidence is lacking, modern sea turtles probably descended from a single common ancestor during the Cretaceous period. Like all other sea turtles except the leatherback, loggerheads are members of the ancient family Cheloniidae, and appeared about 40 million years ago.

Threats

Fishing gear is the biggest threat to loggerheads in the open ocean. They often become entangled in longlines or gillnets. According to the 2009 status review of loggerheads by the Fisheries Service, drowning from entanglement in longline and gillnet fishing gear is the turtles’ primary threat in the North Pacific. They also become stuck in traps, pots, trawls, and dredges. Caught in this unattended equipment, loggerheads risk serious injury or drowning. Turtle excluder devices for nets and other traps reduce the number being accidentally caught.

Nearly 24,000 metric tons of plastic are dumped into the ocean each year. Turtles ingest a wide array of this floating debris, including bags, sheets, pellets, balloons and abandoned fishing line. Loggerheads may mistake the floating plastic for jellyfish, a common food item. The ingested plastic causes numerous health concerns, including intestinal blockage, reduced nutrient absorption and malnutrition, suffocation, ulcerations, or starvation. Ingested plastics release toxic compounds, including polychlorinated biphenyls, which may accumulate in internal tissues. Such toxins may lead to a thinning of eggshells, tissue damage, or deviation from natural behaviors.

Image : By ukanda, CC BY 2.0
Text: Wikipedia contributors. “Loggerhead sea turtle.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 20 Oct. 2017. Web. 27 Oct. 2017.

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