The leatherback sea turtle (Dermochelys coriacea) is the largest living turtle species, distinguished by its flexible, leathery carapace instead of a hard shell. These ancient reptiles undertake vast migrations across the world’s oceans. Reaching lengths of up to 2.4 meters and weighing over 900 kg, their streamlined bodies and powerful flippers enable them to traverse immense distances between feeding and nesting grounds, making them one of the most widely distributed vertebrates globally.
Confirming the Jellyfish Diet
Leatherback sea turtles primarily consume soft-bodied, gelatinous prey, with jellyfish forming the vast majority of their diet. They are sometimes referred to as “gelatinivores” due to this specialized feeding habit. Despite jellyfish being composed of about 95% water and having low caloric content, leatherbacks can sustain their massive size by consuming a remarkable volume. They are known to eat a variety of jellyfish species, including lion’s mane jellyfish and moon jellyfish. Studies indicate they can consume up to 73% of their body weight daily, translating to hundreds of kilograms of jellyfish per day to meet their energy requirements.
Unique Adaptations for Jellyfish Consumption
Leatherback turtles possess several distinct anatomical features enabling their specialized diet. Their mouths feature sharp-edged jaws with pointed, tooth-like cusps on both upper and lower jaws, which assist in grasping and slicing slippery jellyfish. Inside their esophagus, hundreds of backward-pointing spines, called papillae, line the entire length from the mouth to the stomach. These keratin papillae function like a conveyor belt, gripping prey to prevent escape and pushing it towards the stomach, while also allowing the turtle to expel excess seawater ingested during feeding without losing its meal. Their powerful, paddle-shaped front flippers, which can span up to 2.7 meters, facilitate extensive travel to locate dense jellyfish blooms.
Diet-Related Threats
The leatherback’s highly specialized diet, while efficient for natural prey, exposes them to a significant human-induced threat: plastic pollution. Floating plastic bags and other debris can closely resemble jellyfish, leading leatherbacks to mistakenly ingest them, a direct consequence of their feeding habits as visual predators in often murky waters. Studies reveal that plastic has been found in the gastrointestinal tracts of a substantial number of leatherback turtles, sometimes leading to fatal blockages. Ingested plastic can cause internal injuries, obstruct digestion, or create a false sense of fullness, ultimately leading to starvation. This threat highlights the broader conservation challenges faced by these ancient mariners in increasingly polluted marine environments.