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Peter Kienzler
Peter Kienzler
Introduction
Introduction
The leatherback sea turtle (Dermochelys coriacea) is the largest extant species of turtle or tortoise. Weighing as much as 900 kg the leatherback resembles a whale as much as it does a turtle. A relic species with a fossil record stretching back 150 million years it is also the most primitive extant turtle. Capable of reaching depths of 1200 m, it is listed among the deepest diving tetrapods as well. An animal of many extremes the leatherback sea turtle is one of the most unique animals on earth.
The leatherback sea turtle (Dermochelys coriacea) is the largest extant species of turtle or tortoise. Weighing as much as 900 kg the leatherback resembles a whale as much as it does a turtle. A relic species with a fossil record stretching back 150 million years it is also the most primitive extant turtle. Capable of reaching depths of 1200 m, it is listed among the deepest diving tetrapods as well. An animal of many extremes the leatherback sea turtle is one of the most unique animals on earth.
Image by Claudia Lombard (2011), courtesy of Wiki Commons
Image by Scott R Benson (n.d.), courtesy of Wiki Commons
Image by Bernard Dupont (1998), courtesy of Wiki Commons
Taxonomy
Taxonomy
Kingdom: Animalia, the animals
Phylum: Chordata, animals with a dorsal nerve cord
Class: Reptilia, coldblooded scaly skinned tetrapods
Order: Testudines, turtles, sea turtles, and tortoises
Family: Dermochelyidae, the leatherback sea turtle family
Genus: Dermochelys, the leatherback sea turtle genus.
Species Dermochelys coriacea, Latin of turtle skin of leather
Also called the lute turtle, the leather turtle, or simply the lute
Niche and Habitat
Niche and Habitat
Leatherback sea turtles are found throughout the Atlantic and much of the Pacific. A pelagic species, adults spend most of there lives in the open ocean. Though adapted to withstand colder water than other sea turtles, leatherbacks are most frequently seen in warm currents. Females of the species come to land to lay eggs, while males never return to land after hatching. Leatherbacks feed exclusively on soft-bodied invertebrates, particularly jellyfish.
Leatherback sea turtles are found throughout the Atlantic and much of the Pacific. A pelagic species, adults spend most of there lives in the open ocean. Though adapted to withstand colder water than other sea turtles, leatherbacks are most frequently seen in warm currents. Females of the species come to land to lay eggs, while males never return to land after hatching. Leatherbacks feed exclusively on soft-bodied invertebrates, particularly jellyfish.
Full-grown adults have few predators. Though larger shark species such as the bull shark (Carcharhinus leucas) and the great white shark (Carcharodon carcharias) will occasionally take adult leatherback as will orcas (Orcinus orca). Young turtles have many predators including a variety of fish such as snapper (family Lutjanidae) and barracuda (genus Sphyraena), sea birds, ghost crabs (subfamily Ocypodinae). Scavenging mammals such as raccoon (Procyon lotor) and coatimundi (genus Nasau) will consume eggs and hatchlings when available. Humans also feed on sea turtle meat and eggs.
Full-grown adults have few predators. Though larger shark species such as the bull shark (Carcharhinus leucas) and the great white shark (Carcharodon carcharias) will occasionally take adult leatherback as will orcas (Orcinus orca). Young turtles have many predators including a variety of fish such as snapper (family Lutjanidae) and barracuda (genus Sphyraena), sea birds, ghost crabs (subfamily Ocypodinae). Scavenging mammals such as raccoon (Procyon lotor) and coatimundi (genus Nasau) will consume eggs and hatchlings when available. Humans also feed on sea turtle meat and eggs.
Source: Wallace, B.P., Tiwari, M. & Girondot, M. (2013)
Evolutionary History
Evolutionary History
Leatherback sea turtles are a relic species being the only surviving member of the family Dermochelyidae. They are only distantly related to the other 6 extant species of sea turtle which belong to a single-family, Cheloniidae. The carapace or upper portion of the shell is not fused into a single plate in leatherbacks like in most other living turtles. This gives the shell greater flexibility. Adults lack scutes on the shell instead having streamlined ridges running down the back creating the animal's distinct appearance.
Leatherback sea turtles are a relic species being the only surviving member of the family Dermochelyidae. They are only distantly related to the other 6 extant species of sea turtle which belong to a single-family, Cheloniidae. The carapace or upper portion of the shell is not fused into a single plate in leatherbacks like in most other living turtles. This gives the shell greater flexibility. Adults lack scutes on the shell instead having streamlined ridges running down the back creating the animal's distinct appearance.
Perhaps the last true reptilian gigantotherm, the leatherback takes advantage of its large size to regulate its body temperature. Not having to seek out micro-climates to regulate its body temperature allows the leatherback to disperse itself across open ocean and have been found as far north as the arctic circle.
Perhaps the last true reptilian gigantotherm, the leatherback takes advantage of its large size to regulate its body temperature. Not having to seek out micro-climates to regulate its body temperature allows the leatherback to disperse itself across open ocean and have been found as far north as the arctic circle.
The mouth and throat of the leatherback are lined with papillae, backward curving spines. The prey the leatherback sea turtle hunts tend to lack hard structures and often produce defensive mucus. This makes prey difficult to get down. The papillae assist the turtle by preventing the prey from slipping free while the turtle is swallowing.
The mouth and throat of the leatherback are lined with papillae, backward curving spines. The prey the leatherback sea turtle hunts tend to lack hard structures and often produce defensive mucus. This makes prey difficult to get down. The papillae assist the turtle by preventing the prey from slipping free while the turtle is swallowing.
Environmental Impacts
Environmental Impacts
A Leatherback sea turtle can eat on up to 180 kg of jellyfish in a single day. As the top predator of jellyfish in the open ocean, leatherbacks are important for maintaining healthy fisheries. The loss of leatherback sea turtles has been tied to blooms of jellyfish in some areas. Many jellyfish are themselves predators of fish and fish larvae and these blooms have had devastating effects on commercially and ecologically valuable fish stocks.
A Leatherback sea turtle can eat on up to 180 kg of jellyfish in a single day. As the top predator of jellyfish in the open ocean, leatherbacks are important for maintaining healthy fisheries. The loss of leatherback sea turtles has been tied to blooms of jellyfish in some areas. Many jellyfish are themselves predators of fish and fish larvae and these blooms have had devastating effects on commercially and ecologically valuable fish stocks.
Conservation
Conservation
The population of leatherback sea turtle has declined by 90% in recent decades as a result of human action. Turtles frequently become entangled in commercial fishing gear which results in the animal drowning. Plastic pollution is also a major source of fatality, as turtles are often incapable of differentiating soft plastics like those used to make grocery bags food sources. Due to the animal's papillae, trash can become hopelessly tangled in the animal's mouth resulting in choking. Light pollution and erosion of nesting beaches from human activity also play a significant role in reducing the sea turtle's reproductive success. The Endangered Species Act lists the leatherback as endangered. The IUCN lists leatherbacks as threatened due to their declining population but a large range.
The population of leatherback sea turtle has declined by 90% in recent decades as a result of human action. Turtles frequently become entangled in commercial fishing gear which results in the animal drowning. Plastic pollution is also a major source of fatality, as turtles are often incapable of differentiating soft plastics like those used to make grocery bags food sources. Due to the animal's papillae, trash can become hopelessly tangled in the animal's mouth resulting in choking. Light pollution and erosion of nesting beaches from human activity also play a significant role in reducing the sea turtle's reproductive success. The Endangered Species Act lists the leatherback as endangered. The IUCN lists leatherbacks as threatened due to their declining population but a large range.
Friends or Foes?
Friends or Foes?
The ocean is a big place and the leatherback sea turtle has plenty of room to share. As such it competes directly with vary few animals. Though other sea turtles like the loggerhead (Caretta caretta) and the green (Chelonia mydas) also consume jellyfish, these turtles rarely travel as far into the open ocean or can they hunt as deep as the leatherback. As alluded to in a previous section, the leatherback's preference for jellyfish directly benefits pelagic living fish species. Fish including herring (family Clupeidae), mackerel (family Scombridae ), and tuna (subfamily Thunnini) all benefit from the leatherback sea turtle's presence as it controls a major predator. Like many other large marine animals, leatherback turtles also attract a variety of remora or suckerfish (family Echeneidae). These fish use the turtle as a ride in exchange for feeding on parasites and dead skin.
The ocean is a big place and the leatherback sea turtle has plenty of room to share. As such it competes directly with vary few animals. Though other sea turtles like the loggerhead (Caretta caretta) and the green (Chelonia mydas) also consume jellyfish, these turtles rarely travel as far into the open ocean or can they hunt as deep as the leatherback. As alluded to in a previous section, the leatherback's preference for jellyfish directly benefits pelagic living fish species. Fish including herring (family Clupeidae), mackerel (family Scombridae ), and tuna (subfamily Thunnini) all benefit from the leatherback sea turtle's presence as it controls a major predator. Like many other large marine animals, leatherback turtles also attract a variety of remora or suckerfish (family Echeneidae). These fish use the turtle as a ride in exchange for feeding on parasites and dead skin.
Does video of the organism exist?
Does video of the organism exist?
A video of a viscous leatherback seaturtle stalking a terrified school of prey. Set to a funky toon.
Some facts about leatherback sea turtles
TedEd video about the miracle of seaturtles
Web Resources for Audience to Explore
Web Resources for Audience to Explore
Resources
Resources
Conant, R., & Collins, J. T. (1998). Reptiles of North America: Eastern/Central North America. New York: Houghton Mufflin.
Galapgos tortoise. (2020). Retrieved from San Diego Zoo: https://animals.sandiegozoo.org/animals/galapagos-tortoise#:~:text=Adapting%20and%20surviving%3A%20Gal%C3%A1pagos%20tortoises,lying%20down%20to%20conserve%20energy.
Information about sea turtles: Leatherback Sea Turtle. (2020). Retrieved from Sea Turtle Conservancy: https://conserveturtles.org/information-about-sea-turtles-leatherback-sea-turtle/
Leatherback sea turtle . (2020). Retrieved from VA Herpetological Society: https://www.virginiaherpetologicalsociety.com/reptiles/turtles/leatherback-sea-turtle/leatherback_sea_turtle.php
Leatherback sea turtles. (n.d.). Retrieved from SeeTurtles: https://www.seeturtles.org/leatherback-turtles#:~:text=The%20oldest%20of%20all%20sea,have%20taken%20a%20major%20toll.
NOAA. (n.d.). Species directory. Retrieved from NOAA: https://www.fisheries.noaa.gov/species/leatherback-turtle#:~:text=Like%20other%20sea%20turtle%20species,marine%20debris%2C%20and%20climate%20change.
Paladino, F. V., O'Connor, M. P., & Spotila, J. R. (1990). Metabolism of leatherback turtles, gigantothermy, and thermoregulation of dinosaurs. Nature, 344, 858-860. Retrieved from https://www.nature.com/articles/344858a0
Smithsonian Institute. (2018, December). Sea turtles: Cheloniidae and Dermatochelyidae. Retrieved from Smithsonian: Find your Blue: https://ocean.si.edu/ocean-life/reptiles/sea-turtles
Wallace, B. P., Tiwari, M., & Girondot, M. (2013). Dermochelys coriacea. The IUCN Red List of Threatened Species. doi:https://dx.doi.org/10.2305/IUCN.UK.2013-2.RLTS.T6494A43526147.en
Wilson, E. G., Allison, D., & Magliocca, M. (n.d.). Why Healthy Oceans Need Sea Turtles. Oceana. Retrieved from https://oceana.org/sites/default/files/reports/Why_Healthy_Oceans_Need_Sea_Turtles.pdf
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