Sharks are apex predators. But they are also, it turns out, accidental archivists. Peer inside the stomach of one and you may find history, tragedy, pollution — and the occasional musical instrument.

Outdoor Life puts it plainly: sharks use their mouths not only to eat but to explore, which goes a long way toward explaining why inedible objects keep turning up in their guts. For millennia, humans have lost, wrecked, and dumped all manner of things into the sea — and the sharks have been collecting them ever since.

The Garbage Can of the Sea

No shark earns more of the credit — or the blame — than the tiger shark. Maui Ocean Center describes it as "the garbage can of the sea," a species with a highly varied diet whose stomach contents have included license plates, raincoats, and animal antlers.

HowStuffWorks reports that one tiger shark in Australia was found with an entire intact horse's head inside it. Another, caught off the Adriatic Sea, had consumed three overcoats and a nylon raincoat, Outdoor Life notes.

A tiger shark caught off the coast of Senegal offered up something even more eccentric: a traditional animal-skin tom-tom drum, Deccan Chronicle reports.

Medieval Armor, a Florida Plate, and a Bottle of Madeira

The historical record goes back centuries. A 16th-century French physician, Guillaume Rondelet, documented in his published work on marine fish the discovery of a full suit of knight's armor inside a great white shark, Outdoor Life reports. How the armor entered the water remains an open question.

A 1994 traveling exhibit at the American Museum of Natural History in New York put several recovered objects on public display, including a replica of that armor set and a real Florida license plate pulled from a shark's stomach. Outdoor Life suggests the metallic flash of a plate in the water may mimic the glint of a prey fish's scales, triggering a strike.

In 1942, the crew of a French fishing trawler found an unopened bottle of Portuguese Madeira wine in the stomach of a blue shark, Deccan Chronicle reports.

A Reindeer, a Bulldog, and a Murder

Greenland sharks, which can live up to 400 years and grow to 21 feet, patrol the North Atlantic and Arctic. One was found with a complete reindeer inside it — antlers and all, Bustle reports.

In Sydney Harbour, a tiger shark was caught with the head and forelegs of a bulldog still on a leash inside its stomach, Deccan Chronicle reports. Then there is the "Shark Arm" case: a tiger shark held at a Sydney aquarium regurgitated a tattooed human forearm that investigators connected to a murder, We Love Sharks notes.

Songbirds and a Gannet's Leg Band

Perhaps the most surprising modern discovery involves birds — not seabirds, but backyard songbirds. Researchers studying juvenile tiger sharks found bird remains in 41 of the 105 sharks they examined, with species including barn swallows, house wrens, and eastern meadowlarks, Fox News reports. Scientists believe exhausted migratory birds that fall into the ocean become easy targets.

One tiger shark produced something even more detective-worthy: a leg band from a Cape gannet that had been tagged 8,000 kilometers away in South Africa, We Love Sharks reports. The band was recovered some 15 years after the bird was first tagged.

What It All Means

Beyond the spectacle, there is a harder truth. American Oceans notes that sharks are increasingly swallowing non-biodegradable materials — shoes, coal, ropes, fishing gear, cans — as human refuse saturates the marine food chain. The shark's stomach has become an unintentional ledger of everything we put in the ocean.

What ends up inside these animals is not just bizarre. It is a record of us.