Green sea turtles (Chelonia mydas) are among the largest hard-shelled sea turtles, measuring 3 to 4 feet in length and weighing between 300 to 350 pounds. Their name comes from the greenish hue of their fat and cartilage, not their shell, which results from their diet of seagrasses and algae. These herbivorous reptiles play a significant role in marine ecosystems by grazing on seagrass beds, helping maintain the health of these underwater habitats. Found in tropical and subtropical waters globally, green sea turtles are classified as endangered by the International Union for Conservation of Nature (IUCN) and CITES.
Predators of Green Sea Turtle Hatchlings
Green sea turtle hatchlings face many predators during their journey from nest to ocean. These tiny, soft-shelled creatures are vulnerable as they emerge from nests and cross sandy beaches. The mass emergence attracts predators, leading to a high mortality rate where only about 1 in 100 to 1 in 1,000 hatchlings survive to adulthood.
On land, many animals prey on hatchlings. Birds like gulls, frigatebirds, and herons snatch them from nesting beaches. Crabs, including ghost crabs and blue crabs, ambush hatchlings as they move towards the water. Mammals such as raccoons, foxes, wild dogs, coyotes, skunks, opossums, and mongooses also target them.
Even after reaching the ocean, dangers for hatchlings persist. In the water, they become prey for various marine animals. Large fish, including groupers, snappers, jacks, and barracudas, consume young turtles. Sharks, such as tiger sharks and bull sharks, also threaten these small, inexperienced swimmers. Their small size, lack of developed defenses, and the perilous journey across land and into the sea result in the highest predation rates at this early life stage.
Predators of Adult Green Sea Turtles
Adult green sea turtles face fewer natural predators than hatchlings. Their large size, robust shells, and strong swimming provide substantial protection against most marine threats. A healthy, mature green sea turtle is typically too large for most marine animals to prey upon.
The primary natural predators of adult green sea turtles are large and powerful shark species. Tiger sharks (Galeocerdo cuvier) are particularly noted for preying on green sea turtles, possessing strong jaws and serrated teeth capable of crushing their shells. Bull sharks (Carcharhinus leucas) and, less frequently, great white sharks (Carcharodon carcharias) also pose a threat to adult turtles. These apex predators are well-adapted to hunt in the coastal and open ocean environments where green sea turtles reside.
Killer whales (orcas) have also been observed opportunistically preying on sea turtles, including green sea turtles. While more commonly documented with leatherback turtles, orcas have been seen interacting with and preying on green turtles, sometimes using high-speed strikes to stun them. These occurrences are rare and do not represent a consistent predatory threat to adult green sea turtle populations.