WITNESS-Get down! Orcas on the attack

PLAYA PUNTA NORTE, Argentina (Reuters) - The park rangergestured forcefully, ordering me to throw myself down on thesand and stay quiet.

Some sea lion pups paddled tentatively in the shallow surf,learning to swim at Punta Norte beach in eastern Patagonia, andwe were staring at the sea, watching for a huge black fin.

It was my first visit to see orcas hunting baby sea lionson the Valdes peninsula, a natural phenomenon unique to thekiller whale group in this region.

I tried to stick carefully to the instructions the parkranger gave us before leading us to a thin stretch of sand nearthe ocean where Mel, a giant orca, was preparing to hunt.

Six of us -- a Reuters cameraman, the park ranger, threenature photographers, and I -- were waiting to see one of theanimal world's most spectacular attacks on this beach, wherekiller whales swim up a channel of deep water to get right ontothe sand. They risk death if they become stranded.

Stretched out like sharp-shooters 30 yards from water'sedge, we watched, transfixed, as an enormous black finapproached one wobbly pup in the shallow water.

An instant later, Mel torpedoed toward the beach at fullspeed, hidden in a wave and throwing his nine-yard-long bodycompletely out of the water to grab the pup in his jaws.

It was almost soundless. All you could hear was the breakof the waves as the orca shook the sea lion and wiggled hisenormous body on the sand to get positioned for the next waveto carry him back into the water.

SURVIVORS

On the beach, the other pups in the group emerged unscathedfrom the explosion of foam kicked up by the attack.

They were so close to us we could see their eyes. We wereunder strict instructions not to move and mess up the hunt. Anygesture or noise could distract them from the ocean, where theblack fin of another orca loomed.

Having travelled far and waited for hours to see an attack,at first I mentally urged Mel on so we could get a good story.But the little sea lions were cute, and I started to questionmy enthusiasm as Mel's killing continued.

The orcas, the oceans' fiercest predators, come to PuntaNorte every March, staying up to 45 days and building upblubber on a diet of sea-lion pups.

The surviving sea lions are swimming well enough by theSouthern Hemisphere winter to elude the killer whales.

Our visit was carefully orchestrated because experts fearhuman intervention could affect the hunt, perhaps permanently.

Only a few visitors -- researchers, nature photographersand journalists -- are allowed here each autumn, payinghundreds of dollars for the privilege, and escorted byspecialists who control every movement as they record detailsof the hunt for research.

"Grounded with capture, grounded with capture," the rangerbreathed into his two-way radio as Mel took the pup out to seaand shared it with another killer whale.

I stayed face down on the sand until the guide told me Icould sit up for a bit to work out the cramps.

After the first attack, as petrels scarfed up sea lion bitsspit out by the orcas, Mel cruised up and down the coast again,turning 45 degrees on his side to hide his 5-foot (1.5-meter)high fin and watching for more unsteady pups.

For the next several hours only bigger sea lions crossedthe channel area the orcas hunt in. Mel didn't bother pursuingthe strong swimmers, but when the pups returned, the huntstarted up again.

During the two days we spent on the beach, the magnificentanimal, believed to be more than 40 years old, launched himselfonto the sand 14 times and almost always got his pup. A smallerwhale also made a few attempts but failed.

On the third day, the wind changed and the orcas didn'tcome into the channel, but experienced photographers who havespent several seasons watching the orcas said we had been luckyto witness a spectacular two days of hunting.