Habitat and Distribution: Having the widest habitat range of the 7 sea turtle species, leatherbacks can be found from the subarctic to the subantarctic during the summer months. However, juveniles are only found in tropical waters. Leatherbacks have been found foraging in various habitats such as deep offshore waters, as well as shallow coastal waters (Witherington & Witherington, 2015).

Diet: Leatherback sea turtles are a specific type of carnivore known as a medusavore, which means they feed specifically on jellies, comb jellies, and tunicates (Witherington & Witherington, 2015). They are known to eat their weight in jellies daily (Loggerhead Marinelife Center, n.d.).

Size: The average weight of an adult leatherback depends on whether the turtles are in nesting versus foraging season. Nesting female leatherback sea turtles will range from 600 - 1,100 pounds and foraging females can range from 800 - 1,300 pounds. Typical to sea turtle species, males will be slightly smaller than females. The largest leatherback ever recorded was about 2,000 pounds during foraging (Loggerhead Marinelife Center, n.d.). Fun Fact: Loggerhead Marinelife Center biologists have been working on a research study examining the body condition of nesting female leatherback sea turtles to find a baseline weight for this population. This process involves using a scale and pulley system on the beach to weigh the turtle! Check out the 2020 Nesting Season Week 8 Update: https://marinelife.org/2019/05/25/leatherback-nesting-season-week-8-update-body-condition-study/

Distinguishing Characteristics: Leatherbacks are the largest species of sea turtle in the world. Their carapace is not hard like the other sea turtle species, but rather leatherlike with bony plates underneath. Their carapace does not have scutes, but 5 distinct dorsal ridges that extend the length of their carapace. The carapace of a leatherback is a black to blue-black color with white splotches (Witherington & Witherington, 2015). Their leathery carapace allows them to dive to the deepest depths of any sea turtle species because it can compress to withstand extreme pressure (Loggerhead Marinelife Center, n.d.). Leatherbacks’ front flippers are the largest, in proportion to their body than any other sea turtle species and they are lacking claws. The beak of a leatherback has 2 fanglike cusps, which help while eating jellies. On the top of a leatherback’s head, there is a pink splotch that is associated with the pineal gland. Because this pink spot is lacking pigment, it allows for the transmission of light. This may be important in tracking the daily movements of their planktonic prey (Witherington & Witherington, 2015).

Maturity and Reproduction: Leatherbacks grow quickly and have many, varying estimations of when they reach maturity. Some believe leatherbacks reach maturity after 5 years, while others believe it is closer to 15, or even 25 to 30. It is believed that males gather in the waters near nesting beaches but much is unknown about leatherback mating. Typically, leatherback clutches only have 1 paternity (Witherington & Witherington, 2015).

Nesting: Most leatherback nesting takes place in the tropics. These turtles’ nests average 74 viable eggs and also contain smaller unviable eggs, called spacer eggs (Loggerhead Marinelife Center, n.d.). Leatherback eggs are the largest of all sea turtle species, at the size of a billiard ball. Females may lay 4 to 7 clutches and nest every 2 to 3 years. Depending on when they are laid in the season, leatherback eggs will incubate for 2-3 months (Witherington & Witherington, 2015). Nesting in south Florida occurs from March through July. Palm Beach County comprises about 30% of leatherback nesting in the state of Florida. During the 2020 nesting season, 286 leatherback nests were reported on the 9.5 miles of beach that Loggerheads Marinelife Center monitors. Of these leatherback nests, about 46% of eggs studied produce hatchlings according to LMC research (Loggerhead Marinelife Center, n.d).

Conservation and Specific Human Impacts: Over the past 3 generations, the global leatherback population has declined by approximately 40%. Some human impacts that leatherbacks are most at risk of are ingestion of marine debris, entanglement in fishing line, and unintentional boat strikes (NOAA, Leatherback Turtle, n.d.). Leatherbacks feed primarily on jellies, something that many have pointed out may look similar to plastic bags floating in the water.

Local Impacts: Fishing gear injuries and unintentional boat strikes were the most common injuries observed on nesting leatherbacks studied by LMC researchers in 2020. Atlantic leatherback nesting had been increasing but southeastern Florida has seen a decrease in the last 5 years. The cause of this drop has not been determined but could be related to an increase in human-related mortality (Loggerhead Marinelife Center, n.d.). See what our Conservation department is doing to decrease human impacts on sea turtles: https://marinelife.org/conservation/

 

Citations:

Loggerhead Marinelife Center. (n.d.) The Leatherback Project. https://marinelife.org/seaturtles/research/leatherback/

NOAA Fisheries. (n.d.). Leatherback Turtle. https://www.fisheries.noaa.gov/species/leatherback-turtle

Witherington, B., & Witherington, D. (2015) Our Sea Turtles: A Practical Guide for the Atlantic and Gulf, From Canada to Mexico. Pineapple Press, Inc.