By Stacey Venzel
A gentle giant roams the depths of our oceans, and it’s not the blue whale or the giant squid. With a size comparable to that of many small contemporary cars, the leatherback sea turtle is the largest turtle in the world. It can weigh up to 2,000 pounds and reach a length of 7 feet. In 1988, National Geographic reported that a leatherback washed ashore in Wales, shattering the record length at 8.5 feet. The leatherback turtle’s bulk far surpasses that of any other marine turtle and earns it a ranking as the fourth largest living reptile. In the turtle world, the Galapagos tortoise comes in second by a long shot only reaching a maximum weight of about 500 pounds.
The main diet of leatherbacks consists of jellyfish. These soft-bodied invertebrates are not highly nutritious, but leatherbacks are still able to pack on the pounds with them as a meal. A group of four scientists found out exactly how and why this is possible by attaching cameras to a group of the feeding turtles. The study took place in the cold waters of Canada and pointed out two things. First, no jellyfish can outswim a leatherback, which can reach speeds of up to 20 mph. The biologists reported a 100 percent success rate for capture with the chase lasting an average of only 22 seconds. Additionally, leatherbacks consume jellyfish in foraging zones where the gelatinous creatures are found in abundance. These two findings suggest that it is relatively easy for a leatherback to devour its necessary daily intake of 73 percent of its body mass — the equivalent of up to 1,460 pounds of jellyfish.
Unfortunately for the leatherback, floating plastic bags closely resemble jellyfish, and ingestion of such marine debris has proven to be fatal. The National Oceanic and Atmospheric Administration noted that the global population is in decline chiefly due to human-related mortalities including pollution, by-catch and egg harvest. Oddly, marine turtle eggs are considered an aphrodisiac in Asia and Latin America where digging up nests is commonplace.
Not only is the leatherback large in sheer proportion, but it also exhibits the widest geographic range of any reptile. This has caused its red list status to be somewhat of a contention, but all surveys agree the population is vulnerable at the very least. Some subpopulations suggest critical endangerment. CBS News reported that the U.S. government has listed the leatherback population as endangered since 1970—three years before the Endangered Species Act was passed. However, population trends are seeing a slight increase in the Atlantic with help from newly minted protection laws implemented by NOAA. Conversely, the Pacific population continues to head closer to extinction. The International Union for Conservation of Nature forecasted that by the year 2040, only one percent of the total population of leatherbacks will be accounted for in the Pacific.
The ancestral roots of the leatherback sea turtle can be traced back 100 million years to the days when its larger cousin, Archelon, lived in the oceans. Picturing any turtle larger than a Volkswagen is not easy, but there was a time when many existed. Today, organizations and governments around the planet are hard at work trying to protect these ancient, giant denizens of the deep blue sea. With a lot of effort and a little bit of hope, perhaps we can alter the fate of the leatherback sea turtle so that it does not become just an animal in our science books.
- “Leatherback sea turtle.” National Geographic. Web Accessed September 21, 2015. http://www.nmfs.noaa.gov/pr/species/turtles/leatherback.htm
- Heaslip, S.G., Iverson, S.J., Bowen, W.D. & James, M.C. 2012. Jellyfish Support High Energy Intake of Leatherback Sea Turtles (Dermochelys coriacea): Video Evidence from Animal-Borne Cameras. J. PLOS ONE. Web Accessed September 21, 2015. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0033259
- “Leatherback Turtle (Dermochelys coriacea).” National Oceanic and Atmospheric Administration. June 11, 2015. Web Accessed September 21, 2015. http://www.nmfs.noaa.gov/pr/species/turtles/leatherback.htm
- “Turtle egg consumption poses risks to both human health and marine ecosystem.” WWF Indonesia. Web Accessed September 21, 2015. http://www.wwf.or.id/en/news_facts/new_articles/?24441/Konsumi-telur-penyu-ancam-kesehatan-manusia-dan-keseimbangan-laut
- “World’s largest turtle could be extinct in 20 years, experts say.” CBS News. February 28, 2013. Web Accessed September 21, 2015. http://www.cbsnews.com/news/worlds-largest-turtle-could-be-extinct-in-20-years-scientists-say/
- Wallace, B.P., Tiwari, M. & Girondot, M. 2013. Dermochelys coriacea. The IUCN Red List of Threatened Species 2013: e.T6494A43526147. Web Accessed September 21, 2015. http://www.iucnredlist.org/details/6494/0
- “Archelon.” Prehistoric Wildlife. 2011. Web Accessed September 21, 2015. http://www.prehistoric-wildlife.com/species/a/archelon.html