The only surviving polar bear cub of triplets born at the Toronto Zoo last October made his debut on Friday after a recent move from the health centre to a den, where the public can see him.

The male cub's brother and sister died shortly after they were born on Oct. 11. Their 10-year-old mother, Aurora, rejected and wounded them. But the surviving cub wasn't harmed.

He was, however, placed in intensive care and raised away from where Aurora is on display. The cub, now 17 kilograms, is still nameless. The zoo launched a contest Friday for the public to submit their suggestions online.

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Senior veterinarian Graham Crawshaw explained to reporters and visitors on Friday the monitoring that was necessary over the last three and a half months, in a rarely documented case of humans raising a cub from an early age. "This required around-the-clock care," Mr. Crawshaw said.

When the cub was taken from his mother, he was "tiny" at only about 700 grams, Mr. Crawshaw said.

The bear was initially placed in an incubator and fed formula (a high-fat, low-carbohydrate mix meant to simulate bear's milk) from an infant bottle.

The cub's skin – visible on his nose and feet – turned from pink to black when he was about two weeks old, as is normal for polar bears.

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When the cub was about one month old, Mr. Crawshaw said, the bear's eyes and ears opened up. Soon after, his teeth came through.

"He very quickly, and to the delight of many of his caregivers, discovered he could use his teeth," Mr. Crawshaw said.

And then, less than a month ago, the cub learned to walk, he said. On Friday, he was seen for the first time by the public, stumbling around the den he lives in, playing on slabs of ice and rolling in mud.

Mr. Crawshaw said the cub is inquisitive, loves playing with toys and follows around his favourite zoo staff. But he's not perfect. "He can be quite stubborn, he has a temper," Mr. Crawshaw said.

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One of the most famous polar bears born in captivity was Knut, who died last spring at the Berlin zoo, where he had spent all four years of his life.

Abby Smith, a seven-year-old visiting the zoo with her brother, decided after some help from her mom that the cub's name should be Cuddles. "He was really furry," she said.

The naming competition is on the zoo's website and Facebook page. It runs until March 16, then an online vote will be held to pick the most popular name.