Killer whales, or orcas, are often considered the most intelligent marine mammals. Their name is disingenuous in some respects, in that they are more closely related to dolphins than they are to whales, and yet, it is certainly true that they are supremely effective killers. Although they are no threat to humans (at least in the wild), they are considered to be apex predators throughout their global range, as evidenced by their incredibly adaptive, specialized hunting techniques. In some regions, orcas may feed solely on fish, while in others, the same whales may not even recognize fish as part of their diet, preferring to prey instead on mammalian species. Wherever they are, however, the intelligence behind the whales’ hunting techniques, and their tendency to capitalize on strong family bonds by working together when hunting remains the same. This article takes a look at a few of the most remarkable ways in which orcas have become apex predators within varied environments.
Those orcas that feed exclusively on fish have a varied diet, with at least 30 different species recorded as potential prey. The orcas of the Norwegian fjords have developed a unique strategy, known as carousel feeding, for hunting the herring that aggregate there during the winter months. First, the whales work together to separate a small school from the larger shoal, blowing bubbles and startling the fish with flashes of their white undersides in order to corral them towards the surface. Once there, the herring have nowhere to escape and are penned in by members of the orca pod on all sides. The whales then slap the bait ball with their powerful flukes, stunning or killing many fish at once, which the pod can then pick off at leisure. This behavior is unique to Norwegian orcas, and illustrates how the species is able to use teamwork.
In New Zealand, orca populations have developed different, yet equally amazing methods for hunting and killing fish. Here, their major food source appears to be sharks and stingrays, both of which would presumably pose difficulties for lesser predators. Over the years, orcas that prey on these elasmobranches have learned to induce tonic immobility in their prey, thereby lowering their defenses. To do so, the whale must flip the shark or ray onto its back, where it becomes paralyzed and therefore unable to defend itself. In New Zealand, orcas use this tactic to successfully attack thresher sharks, smooth hammerheads, blue sharks and makos, as well as several species of ray and stingray. They have also been observed pinning stingrays to the seafloor before biting them at the base of their tail in order to disable their sting. Inducing tonic immobility is not necessarily unique to New Zealand orcas, though, as at least two instances have been recorded elsewhere. In 1992, two orcas were observed attacking and killing a 26-foot whale shark off Baja California; while in 1997, a female killer whale famously killed a great white near the Farallon Islands off California. The whale was filmed swimming with the shark clenched upside down in her jaws for quite some time, presumably to drown it, as great whites (like many other shark species) must keep moving in order to breathe.
Orcas are also not afraid to prey on other, much larger, whale species. They have been known to attack and kill minke whales, gray whales, sperm whales and even blue whales. Particularly, orcas have learned to take advantage of the annual gray whale migration that takes place along the west coasts of North America and Mexico, seeking out weaker whales or mothers with newborn calves. Once a cow and calf pair has been found, the orca pod will chase the frightened whales until they are exhausted, and when the mother can no longer fight for her calf, they will separate the two and prevent the calf from surfacing until it eventually drowns. This process can take many, many hours; ultimately, the gray whales are usually no match for the stamina and coordination of the orca pod.
Killer whales have developed extraordinary tactics for hunting other mammals too, including many species of seal, sea lion and fur seal. Off Peninsula Valdes in Argentina, and also in the Sub Antarctic Crozet Islands, orcas have learned to beach themselves in order to seize sea lions and elephant seals from their waterside colonies. Female orcas have been observed teaching their calves this difficult and often dangerous technique, pushing them up onto the beach before assisting them back into the water. Similarly, killer whales living in Antarctic regions have learned to create waves that wash penguins and seals off ice floes and into the jaws of pod members waiting on the other side.
That these techniques have developed over time, and are passed down through generations, is clear, as is the level of intelligence they represent. When faced with the proof of this intelligence, it’s clear that these animals don’t belong in captivity. These are magnificent apex predators that can only ever reach their full potential if allowed to remain where they truly belong — in the wild.
