![]() ![]() The fact that it is such a huge herbivore (plant-eating mammal) means that it has just two predators or natural foes. Humans are the only major predators of orca whales on the planet. It has even been reported that they have killed and eaten swimming moose. Fish, squid, seals, sea lions, walruses, birds, sea turtles, otters, other whales and dolphins, polar bears, and reptiles are among the foods consumed by these animals. PREY: The orca is the most important predator in the marine food system. Wolf packs, black bear packs, and grizzly bear packs are examples of predators.įurthermore, do killer whales consume moose? Secondly, what is the natural predator of a moose?Īnimals in the KidZone. A Greenland shark, on the other hand, has been observed preying on moose swimming between islands off the coast of North America’s Northwest Coast. There has only been one recorded instance of a moose being preyed upon by a killer whale (Orcinus orca), which has been known to prey on moose swimming between islands off the coast of North America’s Northwest Coast. They have been seen preying on moose while swimming around the Northwest Coast of the United States.Īlso, does the killer whale prey on or threaten the moose’s existence? Orcas have even attacked moose in shallow waters, Ford says, and in Argentina have been known to beach themselves to grab sea lion pups.The Killer Whale is an important natural predator of the Moose. “They are very adaptable, stealthy, and innovative predators.” “I wouldn’t put it past them,” says John Ford, director of marine mammal research at the Vancouver Public Aquarium in British Columbia. Other experts say Estes’s conclusions about the orcas’ dietary shift are highly plausible. Biologists are still not sure of the reason for this collapse, but a report published in 1996 by the US National Research Council blames overfishing, warming of the North Pacific and whaling as the most likely causes. It is not clear why killer whales have switched prey, but Estes points to a collapse in the populations of northern sea lions and harbour seals in the region during the past two decades. “Just a few top predators can alter their habits and have astounding effects on an entire ecosystem.” “This is the kind of thing a lot of us have worried about,” says Mark Hay, a marine ecologist at the University of North Carolina in Chapel Hill. Its loss may affect seabirds, bald eagles, and other nearshore species. Kelp is the base of the coastal food web and provides habitat for countless fishes, says Estes. As a result kelp beds, on which urchins dine, are disappearing. Populations of sea urchins, the favoured diet of otters, have exploded. The orcas’ new menu has set off a startling cascade. As few as four orcas could have wreaked this havoc by each gulping down about 2000 otters per year. “But it’s conceivable, and not unlikely, that it’s one small group of animals,” he says. “At first I didn’t think it was possible, but we gradually realised that at least some killer whales had switched to preying on sea otters.”Įstes estimates that there are about 150 orcas in the central Aleutians, enough to account for the otters’ decline. He then noticed that otters were thriving in a protected bay inaccessible to orcas. “The magnitude and spatial scale of this decline probably is unprecedented for any carnivore,” says Estes, who reports his team’s work in Science (vol 282, p 483).Įstes ruled out disease, toxic pollutants and starvation as causes for the otters’ plight. About 90 per cent of them have vanished from a 1000-kilometre stretch of the central Aleutians. Since then, a dozen more attacks have been recorded.Įstes has also documented a sharp fall in otter numbers in recent years. Estes and his colleagues first saw an orca attack an otter in 1991. Nevertheless, orcas are now eating otters, claims James Estes, a marine ecologist at the University of California, Santa Cruz. “The whales must be hurting to eat them.” To a killer whale, otters are like “hairy popcorn”, says Paul Dayton, a marine ecologist at the Scripps Institution of Oceanography in La Jolla, California. Orcas usually ignore sea otters, preferring seals and sea lions, which are much larger and provide lots of calories with each blubbery bite. Marine biologists believe that a small band of the voracious predators has devoured more than 40 000 otters since the early 1990s, nearly wiping out otter colonies in parts of the Aleutian Islands. KILLER whales appear to have acquired a taste for Alaskan sea otters-and as a result are transforming the coastal ecology of the region. ![]()
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