Do Tiger Sharks Eat Anything? The Garbage Can Myth Checked

What do tiger sharks really eat?

The tiger shark is a true generalist. It hunts, scavenges and investigates, and its diet reflects whatever is common where it lives. Researchers who have examined hundreds of stomachs from Hawaii, Australia, South Africa and the Americas have recorded an extraordinary list of foods.

Few predators of any kind take such a variety. The secret lies partly in the tiger shark’s teeth: broad, coarsely serrated and hooked to one side, they can cut through bone, tough skin and even turtle shell, as explained in How many teeth does a shark have?

How their diet changes as they grow

Young tiger sharks eat mostly small prey such as fish, squid and crustaceans. A classic 1996 study of tiger sharks in Hawaiian waters showed that the diet broadens as the sharks grow. Once they reach roughly 2.3 m (7.5 ft), large animals such as turtles, birds and mammals become common prey.

As they grow, tiger sharks also develop broader heads and stronger jaws, which help them tackle large, hard-shelled prey. A large adult can take a big animal in several bites, often shaking its head from side to side so that the serrated teeth saw through the flesh.

Sea turtles, dugongs and dolphins

Where they are common, sea turtles are among the most important prey. In some studies, adult turtles have turned up in up to about one in five adult tiger shark stomachs. Species eaten include the green sea turtle, the loggerhead and even the giant leatherback.

Tiger sharks also hunt dugongs off Australia, and many adult dugongs carry scars from failed attacks. Large sharks catch dolphins, especially calves. In Shark Bay, Western Australia, studies showed that bottlenose dolphins avoid rich but risky shallow feeding areas when tiger sharks are most abundant, trading food for safety. Turtles and dugongs change their behavior in similar ways.

Albatross chicks and songbirds

Some of the most surprising meals come from the sky. Each summer, young Laysan and black-footed albatrosses make their first flights from the islands of French Frigate Shoals in the Northwestern Hawaiian Islands. Many land on the water, and tiger sharks gather in the shallow lagoon to catch them. The sharks appear to time their visits to this short fledging season, a sign that they can learn when and where food will be plentiful.

In 2019, scientists reported that young tiger sharks in the northern Gulf of Mexico regularly eat land birds, such as wrens and thrashers. These songbirds fall into the sea from exhaustion during storms on their autumn migration across the Gulf, providing a seasonal windfall for the sharks below.

Scavengers of the sea

Tiger sharks are not just hunters. They readily scavenge dead animals, and groups of them will feed on a floating whale carcass for days, sometimes alongside great white sharks. Off Hawaii, a group of tiger sharks was once recorded feeding on an ailing humpback whale.

Scavenging explains some of the strangest records. Remains of land animals, including goats, rats and even horses, have been found in tiger sharks around Hawaii, probably from carcasses washed or dumped into the sea. Such finds show how much tiger sharks rely on an easy meal, not that they hunt on land.

The “garbage can” reputation

Tiger sharks have earned the nickname “garbage can of the sea” because people have found license plates, tires, cans, plastic bags and other trash inside them. The Florida Museum of Natural History describes a large female caught in the Red Sea that had two empty cans, a plastic bottle and two burlap sacks in her stomach, along with a squid and a 20 cm (8 in) fish.

There are good reasons why trash ends up inside tiger sharks. They often feed in harbors, river mouths and near towns where garbage collects. Like other sharks, they explore unfamiliar objects by biting them. And because they eat such a broad range of prey, they may be less “picky” than other sharks about strange shapes.

Still, the reputation is exaggerated. Trash is found in only some of the sharks examined, and real prey makes up most of what they eat. Swallowed plastic can harm sharks, just as it harms sea turtles and seabirds, so the garbage problem says more about people than about tiger sharks.

Myths and facts

Myth: tiger sharks will eat anything, including people. They have an unusually broad diet, but people are not prey. Serious bites are rare, as the tiger shark profile explains.

Fact: tiger sharks are not truly indiscriminate. They target prey that is abundant and easy to catch, such as turtles near nesting beaches or albatross chicks in the fledging season, and they can travel long distances to find it.