Leatherback turtles are the world's biggest turtles, reaching up to seven feet long and weighing over 2,000 pounds. These reptile relics are the last surviving members of a turtle family with evolutionary origins dating back over 100 million years. The leatherback species is quickly decreasing in many areas of the globe, except for the Arctic & Antarctic oceans.
1. Turtle shell
The leatherback's inky-blue carapace is slightly pliable but almost rubbery to touch, unlike the hard, bony shells of all other sea turtles. The carapace has ridges that help it have a more hydrodynamic structure. Leatherback turtles can swim to a depth of 4,200 feet, the deepest of any turtle, and remain underwater, lasting up to 85 minutes.
2. Population range
Leatherback turtles have the largest worldwide distribution of any reptile and perhaps any vertebrate. In both tropical and temperate waters, they may be found in the Pacific, Atlantic, Indian seas, and the Mediterranean Sea. Leatherback turtles may be found as far north as Canada & Norway.
3. Coldwater adaptations
Unlike their reptile cousins, Leatherbacks can sustain warm body temperatures in freezing water because of a unique combination of characteristics that enable them to produce and retain body heat. These adaptations include large body size, variations in swimming activity & blood flow, and just a thick coating of fat.
Leatherback turtles have the longest migrations of any marine turtle, approximately 3,700 miles each way between feeding and breeding sites. Females come ashore to nest during the breeding season after mating at sea. Digging a hole in the sand, laying approximately 80 eggs, building the nest, leaving a massive, disturbing patch of sand that makes predator identification harder, and ultimately returning to the sea are all part of the nightly routine.
5. Behavior and diet
Leatherback sea turtles travel the most distances between their breeding and feeding grounds of any sea turtle, with some crossing 3,700 miles each trip. Females leave the sea to lay eggs, although they spend most of their life in the ocean. Leatherback turtles are powerful swimmers that can swim to depths of 4,000 feet—the deepest of any turtle—and remain underwater for 80 - 85 minutes.
Leatherbacks lack the crushing and chewing plates that other sea turtles with hard-bodied prey have. Instead, they have sharp-edged jaws and pointed tooth-like cusps, which are ideally suited for food of soft-bodied open seafood like jellyfish and scalps. Backward-pointing spines in a leatherback's mouth or throat aid in the retention of gelatinous prey.
6. Major threats
Entrapment in commercial fishing gear, especially longlines and gillnets, has caused the Pacific population to plummet by almost 90% in the past two decades. Their eggs also are eaten in numerous countries across the globe. Intake of floating marine debris, such as discarded plastics, is also a risk for these ancient animals. When eaten, plastic bags & balloons mimic their preferred prey, jellyfish, and may clog their digestive system, stopping them from eating.