Dedicated to CALIFORNIA TURTLE & TORTOISE CLUB Turtle & Tortoise Conservation, Preservation the Tortuga Gazette and Education Since 1964 Volume 55, Number 5 • September/October 2019 Dermochelys coriacea, the leatherback sea turtle, photographed by Claudia Lombard, USFWS, at the Sandy Point National Wildlife Refuge in the U.S. Virgin Islands. Public domain. Leatherback Sea Turtle, Dermochelys coriacea by M. A. Cohen Ahe leatherback Remarkable sea turtle, The onlyAncient living member of the Marinerche- per hour (0.5–2.8 meters per sec- TDermochelys coriacea, is, by lonian family Dermochelyidae, the ond), (Animals Time, n.d.). any measure, an extraordinary che- leatherback has existed virtually D. coriacea can tolerate ocean lonian. Surpassed by only three unchanged since the Mesozoic temperatures that are much lower saltwater crocodile species in size, Era, the “age of the dinosaurs.” The than other sea turtles can en- the leatherback is the fourth larg- Mesozoic era is divided into three dure. Its front flippers are uniquely est reptile and the largest living periods: “the Triassic period (245- well-endowed with blood vessels, turtle species in the world. 208 million years ago), the Jurassic and this, coupled with insulating Some other amazing facts about period (208-145 million years layers of fats and oils embedded in the leatherback: the species ”lays ago), and the Cretaceous period the thick, leathery skin (1.5 inches the largest eggs of all the turtles, (145-66 million years ago)” (dino- | 3.8 centimeters) on its carapace produces the heaviest clutch- database.com, 2005). contribute to this low-tempera- es of eggs, produces the largest The leatherback is the fastest ma- ture tolerance (Spotila, 2004). hatchlings, migrates the great- rine turtle, swimming in the open The leatherback is the only reptile est distances, grows faster than ocean at a maximum speed of that ventures into frigid sub-Arc- any other reptile, and is among the 21.92 miles per hour (35.28 kilo- tic waters of the North Atlantic widest ranging vertebrates on the meters per hour) with an average during its annual migration to its planet” (Spotila, 2004). swimming speed of 1.1–6.3 miles foraging grounds. During these 2 Tortuga Gazette 55(5) • September/October 2019 C A Remarkable Ancient Mariner by M. A. Cohen 1 Care Society’s Annual Luau by Anita De Leon and John Wong 4 O Some Turtle Embryos Can Influence Their Own Sex by Shreya Dasgupta 8 N Trump Finalizes Disastrous Weakening of Endangered Species Act 9 T Mike’s Turtle Net Picks by Michael J. Connor, Ph.D 10 E Lawsuit Launched to Protect Green Sea Turtle Habitat Threatened by N Sea-level Rise, Plastic Pollution, Warming T Meetings and Programs 11 The Turtle’s Garden: Grapevines (Vitis species) 12 S Herpetology 2019 — CHS Abstracts 14 journeys, the leatherback main- in a blunt point. It features seven temperatures (Spotila, 2004). tains a comparatively warm body prominent, lengthwise ridges Range and Habitat temperature as described in the that enable the leatherback to Distributed throughout the globe previous paragraph. aerodynamically navigate the vast in tropical, temperate, and the Migrating from its nesting grounds expanses of the open ocean during margins of sub-Arctic waters, D. on tropical and subtropical beach- its migrations. Colored white, coriacea has the widest range of es to its favored foraging grounds cream or pale pink, the plastron any marine turtles. in sub-Arctic seas, the leatherback of the species has five lengthwise ridges. Leatherback turtles are found in may navigate as many as 10,000 the North Atlantic waters as far miles (16,093 kilometers) of open Underneath its leathery skin, the north as Newfoundland, Nova ocean. leatherback’s carapace comprises Scotia, and Labrador, and in South The deepest documented dive of many small, interlocking “dermal Atlantic waters as far south as D. coriacea is some 4,000 feet bones” positioned above the ribs Argentina and South Africa. and just beneath the skin. Another (1,219 meters), deeper than any Populations of leatherbacks, while other marine turtle and most ma- unique characteristic of the species’ skeletal structure is that smaller than the Atlantic popula- rine mammals. The species is tion, also range throughout North capable of remaining submerged the ends of its bones feature thick cartilage with an abundance of and South Pacific waters as well as for as long as 85 minutes before it in the Indian Ocean. must surface for air (NOAA Fisher- blood vessels (Spotila, 2004). ies, n.d.). While its rear flippers are pad- The term “pelagic” describes animals that inhabit the open Description dle-shaped, the leatherback’s front-flipper “wingspan”, the seas. D. coriacea is primarily pe- Unlike other marine turtles that lagic throughout its life following have carapaces with keratinized distance from one tip to the other, scutes, a thickened “leathery” or can approach nine “rubbery” skin covers the leather- feet (2.7 meters). back’s carapace. The genus name Proportionately Dermochelys comprises two Greek larger than those of root words, dermo-, meaning skin, other marine turtles, and -chelys, meaning turtle. Mak- its front flippers have ing reference to the hide on its an extraordinary ar- carapace, the species name coria- rangement of veins and cea derives from a Latin root word arteries. These blood coria-, meaning leather. vessels are situated side-by-side, resulting Weighing from 550 to 2,000 in a “counter-current pounds (250 to 900 kilograms) blood-flow heat and reaching a length of up to 8 exchanger” system feet (2.3 meters), the dappled, that enables the leath- black carapace of the leatherback erback to withstand A necropsy photo of the interior of a leatherback’s esophagus. The is teardrop-shaped and terminates frigid sub-Arctic water keratinized spines lining the esophagus face backwards and help the turtle retain the gelatinous foods it favors. Public domain. 3 Tortuga Gazette 55(5) • September/October 2019 hatching, and only female their populations worldwide leatherbacks return to land to are diminishing dramatical- nest. ly. The greatest threat to Foods and Feeding the leatherback’s survival is The leatherback’s migration being trapped as bycatch in from its nesting grounds to its fishing gear such as gillnets, feeding grounds is the stuff longlines, and trawls. Other of legend, hence its reputa- threats include harvesting of tion as an ancient mariner. their eggs, hunting by humans This migratory journey takes for their meat and their skin, D. coriacea from its tropical strikes from the propellers nesting beaches to the gla- and hulls of vessels, alteration cial waters of the sub-Arctic and destruction of nesting North Atlantic and North Pa- beaches, ocean pollution, and cific Oceans. plastic marine debris that may be mistaken for food (NOAA The annual migration of the Fisheries, n.d.). leatherback turtle is a quest Leatherback hatchlings emerge from their nest and head for the for its favorite foods, jellyfish sea. Photo by USFWS Southeast Region. Public domain. In 2012, the state of Califor- and salps, a journey that may nia designated the Pacific leatherback sea turtle as the encompass 10,000 miles. leatherback swims ashore at night official state marine reptile. as well when she is ready to dig a nest and Jellyfish are planktonic, gelatinous as declaring the 13th of October lay her eggs. Estimates vary from marine invertebrates (animals Pacific Leatherback Sea Turtle 8 to 12 days as to the interval be- lacking a backbone) with some Conservation Day. 200 identified species. Like tween nesting events during the jellyfish, salps are gelatinous inver- nesting season. Conservation measures enacted nationally and internationally to tebrates composed of numerous When nesting each season, female protect the declining populations individual organisms linked as a leatherbacks produce one to ten of D. coriacea include listing on chain when mature. clutches of 50 to 100 eggs per Convention on International Trade clutch. These eggs are the largest The carnivorous leatherback also in Endangered Species as Appen- of any marine turtle eggs, weighing consumes cephalopods (cuttlefish, dix 1, the International Union for 2.7 ounces (77 grams) each (Spo- octopus, and squid), crustaceans, the Conservation of Nature’s Red tila, 2004). fish, sea urchins, snails, starfish, List designation of Critically En- marine worms, and zooplankton, Like many other chelonian species, dangered, and the U.S. Endangered among other prey (Farmer, et al., leatherback turtles are subject Species Act listing of Endangered. 2007). to temperature-dependent sex [ Lacking the hard, crushing jaws determination, with a ratio of 50- characteristic of other marine 50 males to females produced at References 85°F (29.5°C). Hatchlings tend to turtles, the leatherback has Animals Time. (n.d.). Leatherback Sea Turtle sharp-edged jaws that are ideal emerge from their nests at night Facts. [online] Available at: for biting soft-bodied prey. Lining which increases their chances of http://animalstime.com/ its mouth, throat and esophagus eluding the many predators that leatherback-sea-turtle-facts-leather- back-sea-turtle-habitat-diet/ are backward-facing spines that lurk on the beach awaiting their arrival (Spotila, 2004). dinodatabase.com. (2005). The Age of Dino- assist with the consumption of saurs. [online] Available at: http://www. gelatinous prey, so the leatherback D. coriacea, being the fastest dinodatabase.com/dinoage.asp is well-suited to digest its prey. growing reptile, reaches repro- Farmer, A., Roszko, A., Fiore, S., Hatton, K., Com- These keratinized, spiked linings ductive maturity in 7 to 13 years bos, V., Helton, A.,s and Fontanes, F. (2007). Dermochelys coriacea Leatherback Sea Tur- in its digestive system equip the (Spotila, 2004), although esti- tle. [online] Animal Diversity Web. Available species to hold and direct its mates of the age of maturity range at: https://animaldiversity.org/accounts/ gelatinous prey into its lower di- from 6 to 29 years (NOAA, n.d.).