Again, Pitman is unsure why, but suggests that it may be simply because so much food was available.īut he adds that orcas need to mate outside their pods, so the gathering to feed on the whale may be a welcome opportunity to socialise with potential partners. The recent Marine Mammal Science paper also notes that, while many orcas, including adult males not in the hunting pod, joined in shortly afterwards to feed on the blue whales, no aggression was observed between any of them. He agrees there may also be some commonality with land-based predators, such as lions, where females do most of the hunting. But the very size of males, he continues, makes them too slow to be effective hunters of whales, which often require long pursuits at speed the female’s body size and shape is ideally adapted for this activity. The male is larger and has a larger dorsal fin, which seems to be sexually attractive to females. There may also be some commonality with land-based predators, like lions, where females do most of the hunting But it is also true that females are better adapted for hunting than males.” “Females need to feed more often, to support their young, so they are more likely to initiate these attacks. He is not sure why this is, but offers a couple of possibilities: While there are adult males in a pod, it is the adult females who do almost all of the serious hunting work in attacking whales. He stresses that orca social groups (pods) are matriarchies, led by a single dominant female, who is generally related to all other members of the group. He also draws attention to how the blue whale attacks reveal a very similar hunting pattern by orcas to that observed previously, albeit this time on larger prey. And as we give protection to whales and they increase, we are going to see conditions we have never seen before. “Those of us alive today,” he told The Irish Times this week from his office in Oregon State University, “have never experienced an ocean that wasn’t largely depleted due to commercial whaling. He thinks it is certainly significant that predation on an adult blue whale has now been proven, but he wonders whether this behaviour is really as exceptional as it might seem from current statistics. He has studied orca predation on half a dozen species of whale, and in a 2015 article in the same journal documented the systematic predation by orcas on the calves of Humpback whales, also in the Bremmer area, which he argues has altered the migration pattern of this huge whale. By 09:20, large chunks of skin and blubber had been stripped off the whale’s flanks behind the dorsal fin it was bleeding profusely and appeared to be weakening as it continued to reduce its swim speed.Ĭo-author Robert Pitman is a marine ecologist and one of the world’s most experienced observers of whales and dolphins. “After approximately 20 min of continuous attack by the killer whales, the blue whale slowed and began swimming in a circle with a radius of about 200 m. Their account of the adult blue whale’s demise concludes like this: They tell of the remarkable, highly co-ordinated social behaviour of groups of orcas hunting down, killing and eating an adult and two calves, in three separate incidents, off Bremer Bay in southwest Australia. Credible accounts of attacks go back at least to the 1970s.īut it has only been confirmed, in detail that is at once coolly scientific and compellingly dramatic, in a paper by John Totterdell and others in Marine Mammal Science late last year ( DOI:10.1111/mms.12906). The news that orcas, or killer whales, the world’s largest predator today, can kill adult blue whales, possibly the world’s largest animal ever, has been long foretold.
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