A pygmy killer whale that beached itself on Maui this month had been escorted for three weeks by a pod of pygmy killer whales, giving marine biologists a rare peek into how the cetaceans cared for one of their own before its death.

Four or five pygmy killer whales had surrounded their 300-pound, seven- to eight-foot, male podmate and appeared to be flipping on their sides and backs to support the struggling mammal, scientists said.

When it grew weaker and came closer to McGregor's Beach, the pygmy killer whales broke off one by one over the next several days and headed back out to the open ocean, where they live year-round in deep Hawaiian waters, said David Schofield, marine mammal response coordinator for the National Oceanic & Atmospheric Administration.

It was the first time that marine biologists had documented such "pre-stranding, milling behavior" in pygmy killer whales around Hawai'i.

"We don't know so much about pygmy killer whales," Schofield said. "... So it was very interesting for us to see this very highly evolved social behavior surrounding the care of this one individual by the other whales."

At a news conference yesterday, Schofield also said that a necropsy revealed that a pregnant, 600-pound Hawaiian monk seal killed Thursday on Kaua'i's north shore had been shot to death.

Witnesses told The Advertiser that they heard four gunshots before they discovered the carcass of the monk seal known to NOAA researchers as RK06 floating in the ocean.

A 4-year-old male monk seal that had been found dead April 19 on a Kaua'i beach also had been shot, Schofield said yesterday.

Schofield would not provide any more details about the two shootings, saying he did not want to jeopardize the investigation. Hawaiian monk seals are federally protected under the Endangered Species Act.

The beaching of the pygmy killer whale also involved unwanted human interaction.

Well-meaning bystanders tried to push the dying mammal back out to sea. But Schofield said they were merely hastening its death — and exposing themselves to being injured by the 300-pound whale or an attack by sharks and other predators potentially attracted to its plight.

The pygmy killer whale had been suffering for at least three weeks and was trying to stay buoyant with the help of his podmates, Schofield said.

"That's a long time," he said. "Any little bit of energy the animal has left is going to be wasted on trying to keep itself afloat. ... You could drown the whale and you could be injured yourself. These animals don't know you're trying to help it."

Although there are hundreds — if not thousands — of pygmy killer whales around the Hawaiian islands, little is known about why they come ashore, Schofield said.

The last beaching of a pygmy killer whale occurred in 2006, when one was found dead at Makaha.

"They are air-breathing mammals and they're trying to support themselves by putting themselves in shallow water on a beach," Schofield said. "There might be a primal instinct. There are those that believe that whales were once land-dwelling animals, so they might have some primal response: 'Hey, I'm sick. I need to go back to shore.' We can't prove that. It's just theoretical."

The whale that beached itself last week had been joined by other pygmy killer whales until only a single podmate accompanied it for the last three days of its life, Schofield said.

The remaining pygmy killer whale itself had barnacles encrusted around its mouth.

On Friday, the elderly male finally beached itself and was getting pounded by waves against a break wall at Ma'alaea Harbor.

"All of his podmates had given up on him," Schofield said.

The whale was taken to the Hawaiian Islands Humpback Whale National Marine Sanctuary complex, where the first auditory test of its kind determined that it did not have any signs of acoustic trauma that could have been caused by such things as Navy sonar, Schofield said.

Hawaiian practitioners performed last rites rituals and Schofield and an O'ahu veterinarian decided to administer a lethal dose of barbiturates.

A necropsy and CT scan conducted on O'ahu later found that the whale was emaciated, missing several teeth, had a low white blood cell count and suffered from pneumonia and liver damage. It had no use of its left lung and only partial use of its right lung.

"We think this was just a very old whale and it was his time," Schofield said. "This whale came ashore and gave to us new knowledge so that we can help other whales in the future."