Whales are the largest animals on Earth, but they are far from invincible. Orcas hunt and kill whales of all sizes, sharks take bites from living whales, humans still hunt them commercially, and when a whale dies, an extraordinary chain of creatures feeds on its body for decades. Here’s a full look at what eats whales, from ocean surface to seafloor.
Orcas: The Primary Whale Predator
Orcas, also called killer whales, are the only ocean predator that routinely hunts and kills other whale species. They target gray whales, minke whales, humpback whales, and even blue whales. Their success depends on teamwork and patience rather than brute force.
When a pod of mammal-eating orcas encounters a humpback whale mother and calf, they develop a coordinated strategy to separate the two. The pod waits for the right moment, then moves in to isolate the calf. Orcas have been observed carrying a kidnapped calf on their backs, mimicking the way a mother whale carries her young in her slipstream, essentially tricking the calf into staying calm. Once separated from its mother, the calf is drowned and consumed by the group.
Calves are the easiest targets, but orcas don’t stop there. Pods have been documented attacking adult gray whales and even adult blue whales, the largest animals ever to live. These hunts can last hours, with orcas taking turns ramming and biting the larger whale until it weakens. In many cases, orcas eat only the tongue and lower jaw, the fattiest and most energy-rich parts of the body, and leave the rest.
Sharks That Feed on Living Whales
Several shark species feed on whales, but the cookiecutter shark has the most unusual approach. This small, cigar-shaped shark latches onto much larger animals and scoops out a round plug of flesh, leaving a crater-shaped wound. At least 49 species of whales and dolphins have been found with cookiecutter shark bite marks. The bites remove conical plugs of blubber and muscle, and while they’re rarely fatal, they leave distinctive circular scars across the whale’s body.
Some whale populations carry far more bite scars than others. Orcas living in open ocean waters off Antarctica and New Zealand show significantly more cookiecutter shark wounds than coastal populations, likely because the sharks prefer deep, warm waters where pelagic animals spend more time.
Great white sharks and other large shark species also scavenge floating whale carcasses. A dead whale drifting at the surface can attract dozens of sharks, which tear through the blubber over days or weeks. This behavior has been filmed repeatedly off the coasts of South Africa, Australia, and California.
Humans Still Hunt Whales
Three countries currently catch whales commercially: Norway, Iceland, and Japan. Norway and Iceland set their own catch limits and hunt North Atlantic minke whales within their exclusive economic zones. Iceland has also taken North Atlantic fin whales. Japan left the International Whaling Commission in 2019 and resumed commercial whaling that same year.
Indigenous communities in Alaska, Russia, Canada, and several other regions also hunt whales under aboriginal subsistence whaling quotas regulated by the IWC. For these communities, whale meat and blubber remain culturally and nutritionally important food sources. Bowhead and gray whales are the most commonly harvested species under these programs.
Scavengers on Shore
When a whale washes up on a beach, it becomes an enormous food source for land animals. A study at Glacier Bay National Park documented what happened when a whale carcass appeared on the shore. Brown bears arrived quickly and fed on it for the entire summer, with as many as six bears eating at the same time. Some bears grew visibly fat from the feast. Whale blubber packs roughly 4,000 calories per pound, compared to about 670 per pound of salmon and just 256 per pound of blueberries. For a bear preparing for hibernation, a single whale carcass is an extraordinary windfall.
Bald eagles also descended on the carcass, with up to 12 feeding at once during the first two months before losing interest. Wolves visited repeatedly throughout the summer, and four wolf pups began joining their parents at the carcass by early August. When the remains finally floated away with the tide in September, a brown bear was still clinging to it, unwilling to let go of the calorie-rich blubber.
The Deep-Sea Whale Fall
When a whale dies and sinks to the ocean floor, it creates an entire ecosystem called a whale fall. In the deep sea, where food is scarce, a single whale carcass can sustain communities of organisms for 50 to 100 years. The process unfolds in overlapping stages.
First, mobile scavengers arrive. Hagfish, sleeper sharks, crabs, and amphipods strip the soft tissue. A large whale carcass can lose several tons of flesh in the first months. Next, smaller opportunists colonize the remaining tissue and sediment around the skeleton, including worms, snails, and crustaceans that graze on bacterial mats growing on the bones.
The most remarkable stage involves the skeleton itself. Whale bones contain high concentrations of lipids (fats), and specialized organisms have evolved to extract this energy. The most famous are Osedax worms, sometimes called “bone-eating worms” or “zombie worms.” These worms have no mouth, gut, or stomach. Instead, they grow root-like structures that bore directly into the bone. Their root cells secrete acid that dissolves the calcium phosphate in bone, while enzymes break down the collagen protein that forms the bone’s structure. The worms themselves handle the collagen digestion, while symbiotic bacteria living inside the roots help process the lipids.
Whale falls have revealed many species found nowhere else on Earth, including specialized snails and a diversity of organisms that feed on the sulfur-producing bacteria that thrive on decomposing bone. These chemosynthetic communities resemble those found at hydrothermal vents, powered not by sunlight but by the chemical energy locked in a whale’s skeleton.
Polar Bears and Opportunistic Feeders
In the Arctic, polar bears scavenge whale carcasses whenever they find them. As sea ice declines and polar bears spend more time on land, stranded whale remains have become an increasingly important food source for some populations. Arctic foxes follow polar bears to whale carcasses and feed on scraps. Seabirds, including gulls, fulmars, and petrels, also gather around floating or beached whale remains in large numbers.
In warmer waters, large fish like groupers and various species of deep-sea fish feed on whale carcasses that settle at moderate depths. Even tiny organisms benefit: bacteria that colonize a dead whale can bloom so densely that they change the chemistry of the surrounding water and sediment, supporting a cascade of microbial life that wouldn’t exist without the whale’s body.