"I didn't see a sow down there, so I'm leaning more towards the fact that they were fighting over territory or dominance," said Cody Ambrose.
The fur-flying battle was captured in a video shot by a resident in the Coquitlam, B.C., home, and the bruins were shot dead.
Ambrose said that when he and his colleagues and police arrived at the house after receiving a 911 call, they saw the scene of a ferocious fight.
"The entire driveway was filled with bear fur, from when the two bears were fighting," Ambrose said of the drama that unfolded Monday morning. "There was blood all over the driveway."
Ambrose said the male bears, each weighing about 160 kilograms, had moved over to the brush near the corner of the house by the time officials arrived. One of the animals was shot when it emerged from the area.
"The other one was up towards another house," Ambrose said. "It almost looked like it was trying to get into someone's shed."
Conservation officers had no choice but to shoot both bruins dead because they were fighting outside a home and were injured, Ambrose said, adding that relocating them would have been problematic.
"You can't just drop them off in an area where there is no food source and have them starve," he said. "That's a horrible way to die. It's not humane."
Drake Stephens, the urban wildlife co-ordinator with the City of Coquitlam, said he was shocked to see the video of the two black bears, biting and clawing at each other.
It is uncommon for bears to fight in the wild, let alone outside someone's house, he said.
"Usually the smaller of the two bears would yield to the other one without fighting and just stay out of his way," he said. "But these two were of equal size and both were alpha males and didn't back down from each other."
Stephens said male bears tend to assert their dominance by marking territory with their scent, marking trees with their teeth and displaying how large they are to other bears.
"They're all about conserving calories and not injuring themselves so they can continue to feed and find food," he said. "They economize their energy very well."
Even though the brawl happened outside a home, Stephens said he isn't too concerned about the animals endangering humans.
"We've had one injury in over 100 years in Coquitlam, and those bears weren't interested in aggression towards people."
-- By Vivian Luk in Vancouver
Note to readers: This is a corrected story. An earlier version incorrectly said the bears fought on Monday night.
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