The 6-month-old cub was found as a newborn by the side of a rural road in St. Malo, 50 miles south of Winnipeg, by Rene and Jeanne Dubois, who hand-reared the cub before turning it over to conservation officials.
The bear, named Makoon, is at the Assiniboine Park Zoo in Winnipeg, and authorities said it would soon be released.
However, animal-rights advocate Judy Stearns has led a protest and 11,000-strong online petition saying the cub is too small and helpless to survive on its own in the wilderness, CTV News said.
"It's the size of a raccoon or a medium-sized dog and we have enough predators in Manitoba that he would be attacked and killed by a predator, or he would die a slow death by starvation," she said.
Stearns and supporters want the 30-pound cub sent to the Bear With Us sanctuary in neighboring Ontario until he is 18 months old, which is when mother bears send their offspring to fend for themselves, the report said.
Conservation officials haven't backed down on the bear's pending release, the date of which wasn't published.