ANCHORAGE (AP) - An orphaned polar bear cub that arrived at the Alaska Zoo two months ago will soon depart for a new adventure: meeting another young cub at the Buffalo Zoo.

Kali made his final Alaska zoo appearance on Monday. He will be flown by UPS from Anchorage to the company hub in Louisville, Kentucky, and then New York, with arrival in Buffalo expected on Wednesday.

A play date with Luna, a nearly six-month old cub born to an adult female at the zoo, could follow in about two weeks.

"The decision to have him with another cub his own age, it's priceless," said Alaska Zoo director Pat Lampi. "They're normally with their mother and another sibling for the first few years of their lives."

The bear's mother was shot and killed by a hunter on March 12 near Point Lay, an Inupiat Eskimo whaling community 460 kilometres southwest of Barrow and 1,100 kilometres northwest of Anchorage.

Polar bears may be killed in defense of life or property, or harvested for subsistence purposes by Alaska Natives, but killing a mother with cubs is not legal under the Marine Mammal Protection Act. US Fish and Wildlife Service regional redirector Geoff Haskett said officials are still investigating.

The tiny cub, estimated to be about five months old, would not have survived without its mother. The next best outcome, Haskett said, is survival in captivity as an ambassador for its species.

"Obviously, it would be better if they could stay in the wild, but that can't happen when they're in a situation like this, so again, our work with the zoo makes the next best thing possible," he said.

Point Lay residents rescued the cub and named it for the Inupiat word for their village. Alaska Airlines flew Kali to Anchorage. Zoo officials recorded his weight at 8.4 kilograms, Mr Lampee said, but Kali is more than triple that at nearly 30 kilograms.

"He's eating almost two pounds of solid food a day in addition to his formula," Mr Lampee said.

The USFWS and the Association of Zoos and Aquariums will work together to decide a permanent home for the bear cub. Veterinarian Kurt Volle of the Buffalo Zoo said Kali likely will be there for six months or so.

Mr Haskett said the key to the Buffalo move was the availability of the other cub.

"It's very, very important early in its life to know how to deal with other bears," he said. If bears are only around humans, he said, they no longer act like a bear.