Sea turtles, ancient marine reptiles with a lineage stretching back millions of years, face numerous threats. Predators pose a significant challenge at every life stage, from egg laying to adulthood. Understanding these predatory pressures provides insight into the complex lives of these creatures.
Predators of Eggs and Hatchlings on Land
Sea turtle eggs, laid in sandy nests on beaches, face immediate threats. Terrestrial predators actively seek out these hidden caches, often digging them up for consumption. Raccoons, foxes, coyotes, and feral dogs are common culprits, alongside smaller threats like ants, rats, and ghost crabs that can access eggs or emerging hatchlings. The scent of eggs and wet sand attracts these animals, making nests vulnerable.
Once hatchlings emerge, they embark on a perilous dash towards the ocean. This short journey across the sand exposes them to numerous predators. Birds such as gulls, night herons, and other seabirds swoop down to snatch the tiny turtles. Ghost crabs, lurking in the darkness, also pose a significant threat, ambushing hatchlings as they crawl towards the surf. The high number of predators and slow movement of hatchlings contribute to an extremely high mortality rate during this land-based phase.
Predators of Hatchlings in Water
Dangers for sea turtle hatchlings continue once they reach the ocean, where marine predators await. As these tiny turtles enter the water, they begin a “swimming frenzy” to escape immediate nearshore threats. This initial swim puts them in direct contact with hungry marine life. Large bony fish, sharks, and diving seabirds actively prey on these vulnerable newcomers.
The vastness of the ocean presents both a refuge and a challenge, as hatchlings disperse into their “lost years.” During this period, their movements are difficult to track, but they remain susceptible to predation from larger marine species. While “safety in numbers” might offer some protection, the abundance of predators means only a small fraction of hatchlings survive this initial marine phase. Many experts suggest that as few as one in 1,000 to one in 10,000 hatchlings survive to adulthood.
Predators of Juvenile and Adult Sea Turtles
As sea turtles grow, their size and hardened shells offer increased protection, reducing their natural predators. However, they are not entirely immune. Large shark species, particularly tiger sharks, prey on both juvenile and adult sea turtles. Tiger sharks possess specialized teeth and strong jaws that allow them to cut through a turtle’s thick shell, hunting them in shallow seagrass beds, coral reefs, and the open sea.
Orcas, or killer whales, are also occasional predators of adult sea turtles, especially leatherbacks. In certain coastal areas, large crocodiles, such as American crocodiles and saltwater crocodiles, can pose a threat to nesting female turtles on beaches or in inshore waters. While natural predation decreases with size, human activities introduce new dangers.
Humans represent a significant threat to sea turtles across all life stages. Poaching for meat, eggs, and shells has historically decimated populations. Incidental capture in fishing gear, known as bycatch, leads to thousands of sea turtle deaths annually. Turtles become entangled in nets like shrimp trawls, gillnets, and longlines, often drowning or suffering injuries.
Marine pollution, including plastic ingestion, also contributes to mortality, as turtles may mistake plastic for food, leading to internal blockages or starvation. Habitat destruction and coastal development further impact nesting sites and foraging grounds, disrupting their life cycle and increasing their overall vulnerability.