Leopard seals suck up krill like whales
Source: Ed Yong, Nature
The leopard seal (Hydrurga leptonyx) is one of Antarctica’s top predators. It kills penguins and smaller seals by biting them with sharp canine teeth and repeatedly smashing them against the ocean surface to flay and dismember them. But it now seems that this seal is also equipped to tackle smaller prey.
David Hocking from Monash University in Melbourne, Australia, and his colleagues have shown that the leopard seal eats krill like a whale, by sucking them into its mouth and sieving them through special teeth. Other scientists had predicted this behaviour from the shape and arrangement of the seal’s teeth, but this is the first time that it has been observed and filmed. The researchers' results are published in Polar Biology1.
By switching between two feeding styles, the leopard seal can dine from both the top and bottom of the Southern Ocean’s food web. “This is equivalent to a lion hunting down zebras, but also regularly feasting on ants or termites,” says Erich Fitzgerald from Museum Victoria, Melbourne, who was involved in the study.
“You’d expect that leopard seals would sacrifice something in not specializing on either large or small prey, but the authors persuasively argue that it is a dual specialist,” says Alexander Werth, a biologist from Hampden-Sydney College in Virginia. “This helps to explain why leopard seals are so successful.”
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