There was a furry surprise waiting for a driver who stopped to use the restroom in the Rocky Mountains last weekend. 

The motorist stepped into a roadside washroom in Banff National Park, near Vermillion Lakes, on Saturday to find three young black bears trapped inside.

Parks Canada said the cubs' mother was nowhere in sight, and it's unclear how the bears ended up inside the restroom.

"We have no clue," spokeswoman Christina Tricomi said. "We have an investigation open right now."

The bears were in good condition, and it's unlikely they had been in the busy washroom for long, she added.

They’re too young to be on their own, however, so staff scooped up the roughly three-month-old bears and are hoping to place them in a rehabilitation facility.

"They're too young to survive without their mother. Usually black bear cubs are with their mother for about a year," Tricomi said.

Ideally, the cubs will eventually be released back into the park ecosystem.

Anyone with information on how the bears ended up in the restroom is asked to call Parks Canada.