Witnesses described Wednesday how they saw the dolphin swim up to two stranded whales and guide them to safety.
Before Moko arrived, rescue workers had been working for more than an hour to get two pygmy sperm whales, a mother and her calf, back out to sea after they were stranded Monday off Mahia Beach, New Zealand Conservation Department worker Malcolm Smith said.
But Smith said the whales restranded themselves four times on a sandbar slightly out to sea from the beach, about 300 miles (500 kilometers) northeast of the capital, Wellington.
It was looking likely they would have to be euthanized to prevent a prolonged death, he said.
"They kept getting disorientated and stranding again," said Smith, who was among the rescuers. "They obviously couldn't find their way back past (the sandbar) to the sea."
Then along came Moko, who approached the whales and appeared to lead them as they swam 200 yards (180 meters) along the beach and through a channel out to the open sea.
"Moko just came flying through the water and pushed in between us and the whales," Juanita Symes, another rescuer, told the Associated Press. "She got them to head toward the hill, where the channel is. It was an amazing experience."
Anton van Helden, a marine mammals expert at New Zealand's national museum, Te Papa Tongarewa, said the reports of Moko's rescue were "fantastic" but believable because dolphins have "a great capacity for altruistic activities."
There's evidence of dolphins protecting people lost at sea, and the swimmers are known for their playfulness with other animals.
"But it's the first time I've heard of an inter-species refloating technique. I think that's wonderful," said van Helden, who was not involved in the rescue but spoke afterward to Smith.
Copyright 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
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