A favorite prey is the red squirrel. Martens are solitary and nocturnal animals, but usually feed during the day when prey is most abundant. They are somewhat arboreal and spend much of their time dwelling in trees, but are also at home in the water. Active all winter, martens can suppress their body temperature many degrees, therefore minimizing energy expenditure. Breeding occurs between June and August.
Home ranges vary with habitat and prey density.
Like its larger cousin the fisher, the marten needs overhead cover. They have one of the narrowest ranges of habitat types of all forest carnivores and are rarely seen above the tree line. Historically the marten was widespread throughout the Rocky Mountains and Pacific Northwest. Although not as effected as other species, the marten has suffered some loss of habitat due to logging and trapping. Today the marten is found in patchy populations of fragmented forest habitats.