Mustelids do not hibernate or go into torpor, and must hunt all year. Their elongated shapes result in heat loss, and they must consume more calories to make up for that. The result is an animal intent on finding and killing prey. Mustelids in temperate regions exhibit delayed implantation . One male may mate with several females during the breeding season.
Females are monestrous and cycle shortly after parturition.
Mustelids are active at any time of the day or night, that is, not typically just nocturnal or diurnal. They are important as furbearers and predators, and serve important ecological roles at the top of the foodchain. They are solitary and territorial, males having larger territories than females. They are arboreal mustelids, that is, very adept tree climbers. They will often travel through trees, and can prey on birds, eggs and squirrels.