Tiger sharks find green turtles particularly tasty but, when hungry, any handy turtle will do. Leatherbacks, whose Atlantic nesting grounds coincide with tiger shark offshore nurseries, are easy prey for the aggressive shark. The turtle's leathery carapace, with its rubbery skin stretched over small bones and ridges, cannot protect it from shark's teeth. Although leatherbacks are powerful swimmers, they can't swim backward, and the tiger shark attacks swiftly. Leatherbacks, like all other sea turtles, have nonretractable flippers and cannot pull their heads inside their shells like land turtles, so they present even more vulnerable surface area for a hungry shark.
Tiger sharks spend much of the fall into early summer around coastal areas, feeding on turtles. Late summer to early fall is the typical hatching period for baby leatherbacks and other sea turtles, and many of the hatchlings are picked off by sharks, sea birds and other predators as they enter the water for the first time. In some areas, sea turtles dig their nests in the late spring and early summer, an activity that brings the adults into coastal waters in greater than normal concentrations, which makes hunting easy for tiger sharks.
The great white shark spends much of its time in the epipelagic layer of ocean, the depths from the surface down to where the temperature drops off. As leatherbacks and other turtles are reptiles that breathe air, they too are typically found in the epipelagic layer--sometimes by great white sharks. Great whites eat whatever they want, and that includes all kinds of sea turtles. Their mouths are large enough to swallow prey whole, and their fearsome, saw-edged teeth can rip right through a leatherback's carapace to kill it and tear it into big chunks, which the shark gulps down.
Great Whites have been spotted near the coastlines of the eastern United States--both Atlantic and Gulf coastal areas--and off California up to Alaska on the West Coast. Their range includes Hawaii, South Africa, most of South America and Australia, New Zealand and the Mediterranean Sea, crisscrossing the leatherback turtle nesting areas as well as the sea lanes the big turtles travel in search of the jellyfish that is a staple of their diet.
Short-finned mako sharks hover by day near the continental shelf and move in close to shore at night to feed. The mako prefers fish, but it will eat other sharks, sea snakes, marine mammals, rays and sea turtles. The mako's usual range is similar to the nesting range of the leatherback turtle.
Bull sharks are very aggressive and live mostly in coastal areas in the shallows between islands and near docks. They are almost as large as great whites and eat a varied diet that includes opportunistic kills of sea turtles, including leatherbacks, and dolphins.
The oceanic whitetip shark can grow up to 13 feet long, likes to travel with pods of whales and will eat all kinds of turtles, stingrays, squid, seabirds and marine mammal carrion. It spends most of its time in the ocean areas where adult leatherbacks go to feed.