Mink react to boredom in much the same way as humans - by eating too many snacks and idling away their time, scientists have found.
Researchers believe the findings show captive animals can suffer psychologically from a lack of things to do.
The scientists compared mink living in small, bare cages with those housed in large enclosures containing passageways, water pools, climbing towers and chewable toys.
"We don't know whether mink or other animals truly feel bored in the same way that humans do," said researcher Dr Rebecca Meagher, from the University of Guelph in Ontario, Canada.
"We can't measure that type of subjective experience. But we can see that, when they have little to do, then just like many bored humans, they may look listless, and, if given the chance, eagerly seek any form of stimulation."
The findings are reported in the online journal Public Library of Science ONE.