A Parks Canada wildlife specialist says he suspects a 250-kilogram grizzly gobbled down a smaller grizzly because … he was really, really hungry.

Steve Michel, a human-wildlife conflict specialist with Banff National Park, says staff discovered the carnage last month after a radio collar was lost by Bear No. 136, nicknamed Split Lip because of a massive scar on his mouth.

When they went to retrieve it, they also found the fully consumed carcass of another, smaller grizzly.

"There really was nothing left except a skull and some hair samples," said Michel.

Park officials have confirmed it was Bear No. 132, a male grizzly that weighed 90 kilograms. Split Lip is almost three times his size — around 250 kilos, says Michel.

Bear No. 136, known as Split Lip, ambled through the parking lot at Johnston Canyon this week. (Amar Athwal)

Because so little was left of the smaller bear, park staff can't be 100 per cent certain he died at the paws of Split Lip.

But Michel says that's what likely went down.

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"In the past, we have had some incidents where we have documented for sure large male grizzly bears killing other mature grizzly bears smaller than them… So it's a strong possibility that that's what happened in this case."

Poor food year for predators

It's been a poor food year for predators in Banff National Park and surrounding areas, says Michel.

For one, berry crops that bears often feast on were quite limited this year.

"The animals were food-stressed and they didn't have nearly as much fat on as they'd like going into the den," he said. "Bears are very opportunistic. They'll take advantage of any sort of predator event that they're capable of."

"There's no question" bears in the area are skinnier than they should be at this time of year, said Michel.

He says juvenile and female bears will be heading into hibernation any day now, but big grizzlies like Split Lip could be out foraging until Christmas.