Evolution and systematics
The leatherback seaturtle ( Dermochelys coriacea) is most carefully associated to the opposite marine turtles of the household Cheloniidae. The household Dermochelyidae is understood from the Eocene to the Pliocene in Africa, Europe, Japan, Antarctica, Peru, and North America. The Pacific and Atlantic populations differ genetically and have been acknowledged as separate subspecies by some authors. This seaturtle can be generally often called caldon (Trinidad), canal (Caribbean, Latin America), caouana (Carib Indians), cardon (Venezuela), laúd, luth, and trunk turtle. No subfamilies are acknowledged. The taxonomy of this species is Testudo coriacea Vandelli, 1761, Mediterranean and Adriatic seas.
The easy, streamlined carapace is teardrop formed (up to 96 in [244 cm] in size), bears seven longitudinal ridges, lacks epidermal scutes, and is roofed with leathery pores and skin. Most of the bones of the carapace have been misplaced, however a mosaic of a whole bunch of small dermal bones lies slightly below the leathery pores and skin. The head additionally lacks scales and has a distinguished toothlike cusp on both sides of the higher jaw. The shell and pores and skin are typically black with scattered white or yellow blotches or spots. The plastron is predominately white with scattered darkish blotches or spots. The forelimbs are paddle-like and lack claws.
This pelagic species has maybe the best distribution of any reptile. It is present in all tropical oceans (and within the Mediterranean Sea), and it additionally ventures into the chilly temperate waters round Newfoundland, Iceland, Norway, the Cape of Good Hope, New Zealand, and Alaska. Its nesting is on tropical and subtropical shores.
This species is pelagic, and is just not often present in shallow our bodies of water.
Leatherback seaturtles make in depth migrations between feeding and nesting areas. Recaptures have been made greater than 3,100 mi (5,000 km) away, and people have traveled a median of greater than 19 mi (30 km) per day for weeks at a time. Feeding takes place in each chilly and heat water environments, largely as a result of leatherbacks can preserve physique temperatures above environmental temperatures. Body warmth generated by muscle exercise is misplaced very slowly due to the thermal inertia of the big physique, wonderful insulative properties of the oily pores and skin, and countercurrent circulatory system within the limbs which retains the warmth within the physique’s core. Leatherbacks generally mixture, in all probability in affiliation with feeding (e.g., on faculties of jellyfish). They are also able to making dives to depths of greater than 3,300 ft (1,000m) to attain food sources. They are lively each day and night time, though diving exercise is elevated at night time. As they depart the nest, hatchlings are attracted to open, extremely illuminated areas (often the open sea).
Feeding ecology and eating regimen
Leatherbacks are nearly fully carnivorous, preferring oceanic jellyfish. However, in addition they eat hydrozoans, snails, bivalves, octopi, squid, amphipod crustaceans, crabs, sea urchins, tunicates, and small fish, in addition to algae, kelp, and sea grasses. Unfortunately, plastic luggage or balloons dumped within the ocean by people are sometimes mistaken for jellyfish and, if consumed, can block the gastrointestinal tract, inflicting the turtle’s loss of life.
Based on progress rings fashioned yearly within the lengthy bones of leatherbacks, ####ual maturity is reached at about 13 to 14 years. Courtship and mating have solely not often been noticed, and are recognized to happen in tropical water (e.g., close to nesting seashores), however can also happen earlier than or throughout migration to the nesting seashores. Nesting happens on a large number of tropical seashores, however the variety of females utilizing a given seaside is commonly small, and the numbers at even the very best websites are declining. Atlantic leatherbacks nest from April to November; these from the Pacific nest at varied instances of the 12 months relying on the situation. Nesting is often at night time, and takes place simply above the excessive tide line, on open sandy seashores freed from rocks, and many others., that will abrade the tender plastron. The feminine digs an enormous physique pit with each forelimbs and hind limbs, after which excavates the precise nest cavity together with her hind toes. Once the eggs are laid, the opening to the nest cavity is roofed with sand by the hind limbs, and ultimately the forelimbs are additionally used to fill the physique pit. Eggs are spherical, with pliable shells, and are 1.9-2.6 in (49-65 mm) in diameter and weigh 2.5-3.2 oz (70-90 g); nevertheless, from one to 103 undersized (0.6-1.eight in [15-45 mm]) and yolkless eggs could also be produced together with the conventional egg complement, which numbers from 46 to 160. Clutch and egg dimension each have a tendency to enhance with feminine dimension. Clutch sizes are additionally typically bigger on Atlantic seashores than on jap Pacific seashores, and clutches laid in the course of the center of the nesting season are often bigger than these in early or late nests. Females oviposit up to 11 instances throughout a nesting season, though half that many clutches per season is extra normal. Females nest solely each two or three years. Incubation requires 50-78 days, however most undisturbed nests apparently hatch in 60-68 days. Most hatchlings depart the nest at night time. S*x is set by temperature in the course of the center third of incubation, with solely females produced at excessive temperatures and solely males at low ones.
This species is listed as Critically Endangered on the IUCN Red List, as Endangered by the U.S. Fish and Wildlife Service, and in Appendix I of the CITES.
Significance to people
Population estimates counsel that this species has declined by greater than 70% in lower than one era. Egg poaching has been the first cause for the decline on this species, though adults are additionally harvested in lots of areas for his or her flesh and/or the oil of their shells.