(covers information from several alternate timelines)
A Cardassian vole was an animal native to Cardassia Prime. Cardassian voles were about twenty-five centimeters long, had little hair on their bodies, and were generally regarded as pests. They had six legs and were attracted to energy fields. Voles featured spoon-shaped impression on their foreheads, similar to those of Cardassians, and lines at the base of the cheeks (under the ears).
A pair of mating voles were said to "breed like tribbles", but that "they're not as cute." They had even been described as "disgusting hairy little creatures with ravenous appetites." They lived in nests, and were known to create secondary nests in addition to the main one. (DS9: "Ferengi Love Songs")
Deep Space 9 suffered an infestation of voles in formerly uninhabited sections of the station. After the supposed eradication of the infestation, Quark's suffered from a further infestation in 2373 and had to be temporarily closed down while they were exterminated. (DS9: "Playing God", "Ferengi Love Songs") Later that year, when crewman Pechetti expressed excitement about bringing a phaser along to Empok Nor, his fellow crewman told him that the only thing it would be good for would be "shooting voles," though it was unknown if the station was actually infested. (DS9: "Empok Nor")
Although illegal in Bajoran space, it was possible to train Cardassian voles to fight. Quark was warned at least once by Odo that no live vole fights would be permitted on the station, and both he and Morn were once caught by Odo preparing a number of voles for a fight. (DS9: "Destiny", "Through the Looking Glass") There was apparently a market for their bellies. (DS9: "Body Parts")
These voles were the subject of a number of colorful expressions. When complaining about Chief O'Brien's bedside manner, crewman Enrique Muniz stated that he had "known nicer voles. Certainly prettier ones." (DS9: "The Ship") Two individuals engaged in intense sexual activities were said to leap on each other "like a pair of crazed voles." (DS9: "Looking for par'Mach in All the Wrong Places") An individual who was particularly ill was said to be "sick as a vole." (DS9: "The Assignment") Vargas described AR-558 as a "vole hole" and demanded to be removed from it, noting that Starfleet regulations stated that ground personnel were to be rotated off the front lines every ninety days. (DS9: "The Siege of AR-558")