A motorist who stopped along the Trans-Canada Highway west of Banff found a bigger call of nature than expected — three bear cubs packed inside a washroom.

Now Parks Canada officials in Alberta are trying to figure out how the cubs got trapped in the facility at the Vermilion Lakes turnout just west of the Banff townsite.

The cubs were found by the motorist on April 1.

"I have no idea how they came to be there," said Sheila Luey, acting superintendent for the Banff field unit.

"We searched the area extensively for the first 36 hours after they were found and couldn't find any sign of the mother, nor could we find any sign of bear activity in the area."

These bear cubs are now in the care of Parks Canada staff, who are hand feeding them since they're so young they would still have been reliant on their mother's milk. (Parks Canada)

The cubs are about three months old. Luey said they weigh about two or three kilograms each.

They're now in the care of Parks Canada.

They are being hand fed, since they would still have been reliant on their mother's milk, Luey said.

"They stick very close to their mother when they're that young," she said, explaining that immediately releasing them into the wild is not possible.

Parks Canada says it is not at all clear how the cubs got locked in this washroom at the Vermilion Lakes turnout just west of the Banff townsite. (Dave Gilson/CBC)

Wardens are looking at several options, including relocating the cubs to a rehabilitation facility or a certified zoo.

Clio Smeeton, who runs a wildlife rehab facility at the Cochrane Research Institute west of Calgary, said the best outcome for the cubs and their species would be for the animals to eventually end up back in their natural habitat.

While it's not uncommon to see black bears in the Rocky Mountains, she said the species only occupies about one-third of its historic range in North America.

"It has lost two-thirds of its genetic biodiversity, which makes every individual important," she said.

"So the most important thing is that those cubs are reared and released back into the wild."

Anyone with information about the bears is asked to call Parks Canada at 403-762-1470.