The report, published in this month's Journal of Zoology, says polar bears have enlarged sweat glands in the pads of their feet.
Ten years ago, the San Diego Zoo asked Polar Bears International to swab between the toes of polar bears' feet using Q-Tips.
"I think they probably thought we were crazy when we made the request," said biologist Megan Owen.
The researchers then exposed the scent samples to bears of different sex and age groups. From the samples, they identified pheromones and other chemicals even in minute quantities, and found bears can smell the scents left by the tracks on the ice despite great distances and lapses of time.
Steven Amstrup, a chief scientist with Polar Bears International, says that highly adapted method of communication could be in jeopardy.
"Less sea ice and also a more broken, more disrupted sea ice surface may have other threats, and one of those is that these creatures may not be able to find each other when they need to breed."
Both Owen and Amstrup say hunters' knowledge confirms that polar bears follow some tracks and not others, but that has not been studied by researchers until now.Suggest a correction