Marine Killer That Lives Off The Land

Thursday, April 17, 2008
PLAYA PUNTA NORTE, ARGENTINA - It is a sight unique in the natural world and proof, if ever it were required, of Lord Tennyson's description of nature as "red in tooth and claw". An orca, or killer whale, to give the creature its more appropriate title, torpedoes out of the water on to a beach to snatch a sea lion pup between its powerful jaws.

This hunting technique, which defies instinct and risks stranding the whale, is practised by just seven orcas in the world, all members of a particular pod that patrols the coast of Patagonia's Valdes Peninsula each March and April, when young sea lions are learning to swim.

Captured by the camera is Mel, a six-tonne, 30ft orca that was shadowed by a younger killer whale, learning the skill but as yet too timid to try it.

One of the pod's favourite hunting spots is at Playa Punta Norte, the northern tip of the peninsula, where a deep channel leads up to the sand, passing between two rocky areas where sea lions breed.

The sea lion pups learn to swim by crossing the channel between the rocks. Once they can swim well, they are too fast and agile for the orca. But the youngest ones, which stay on the sand at the water's edge, are perfect prey. The orcas can beach themselves several times a day, but this hunting method is risky. Whales can die if they remain out of water, so they have to time the waves and judge distances carefully. They use sonar to hunt, and beach themselves only in high tide, on steep and pebbly beaches that help them roll back.

Orcas are highly social and long-lived: females can live up to 80 years and males almost 60. But the pods grow slowly because orcas take at least 15 years to mature, the females have calves only every five years or so and many of them die young. Yet this novel hunting technique was in danger of dying out.

"It's a culture at risk," explained Roberto Bubas, a ranger with 15 years' experience of observing orcas in Patagonia, who said of the seven orcas, only five were teaching the technique to younger members of the pod.

Each year the orcas, sea lions and penguins attract around 340,000 tourists to the Valdes Peninsula and last year 36 cruise ships made stops nearby, three times as many as in 2002.

However, only documentarists, researchers and some journalists are allowed access to the beach at Punta Norte, and they must pay for the privilege. The money goes to the provincial government, which administers the reserve.

Hunting In Packs

The orca, also known as the seawolf on account of its predatory manner, is the largest species of the oceanic dolphin family and can be found across the world's oceans.

The Blue Planet, the BBC's critically acclaimed natural history series, has broadcast footage of a pod of killer whales hunting grey whales, separating the youngest and weakest from its mother, killing it, then devouring only the tongue.

While wild orcas are rarely a threat to humans, captive orcas have occasionally attacked handlers at marine theme parks.

Watch the footage of Mel the orca in action

Source: The Scotsman News