David Hocking: Leopard seals are one of the top predators in the Antarctic ecosystem. They're infamous for feeding on large prey, such as penguins and seals, which they capture by ambushing them at the water's edge. But what's interesting about these seals is that they're also able to feed on much smaller prey, and most importantly, Antarctic Krill.
What we've found by working with the seals at Taronga Zoo, is that when they're feeding on small prey, leopard seals are able to use suction to draw the food item into their mouth, before they push their tongue to the roof of the mouth, forcing out the water whilst trapping the food items behind the sieve created by the cheek teeth.
Dr. Alistair Evans: Once we've been able to observe these animals in captivity, we wanted to find out if they did similar things in the wild. To do this, we looked at a large collection of specimens in Museum Victoria. We looked at all of these skulls to see how the wear on the teeth in the front and the back may have told us about how they were being used.
We found that the wear on these front teeth meant that they were probably used for piercing large prey. We found very little of this type of wear on the back teeth. So this is very consistent with the front teeth being used to puncture through large prey and shake apart prey like penguins and seal pups, while the back teeth were used for sieving small prey and keeping it within their mouth.
Dr. Erich Fitzgerald: Despite their popularity and charismatic nature, the very habitat and lifestyle of marine mammals, like the leopard seal, make it quite difficult for scientists to unravel the mysteries of their lives, but also their evolution. It is really only with integration of the study of museum specimens, such as this skull of a leopard seal, as well as observations of live animals, like the opportunity presented by Taronga Zoo, that we can really get to the bottom of the mysteries of the lives of marine mammals.
David Hocking: Leopard seals are one of last truly abundant mammalian predators, with numbers perhaps as high as 100,000 individuals living in the wild. But these top predators are living on the Antarctic pack ice, which is one of the ecosystems that will be most heavily affected by any changes to the world's climate, putting these amazing predators and the other iconic Antarctic fauna at risk.