Deer Mouse

Peromyscus maniculatus, the deer mouse, is a small rodent belonging to the family Cricetidae. Adults typically measure 14–22 cm in total length, with a tail comprising 40–50% of this, and weigh 15–32 grams. They are characterized by distinctly bicolored fur: reddish-brown to grayish-brown dorsally and pure white ventrally, extending to their feet and often to the underside of their tail. Their reproductive capacity is significant, with females capable of producing 3–4 litters annually, each containing 3–7 altricial young, after a gestation period of 22–27 days. Sexual maturity is reached rapidly, often within 7–8 weeks, and their maximum lifespan in the wild is typically 1 year due to predation, though laboratory conditions allow for up to 8 years.

Primarily nocturnal, deer mice exhibit crepuscular activity with foraging peaks at dusk and dawn, though they can be active throughout the night. They are highly agile climbers, making extensive use of vertical structures and vegetation for foraging and evasion. While generally solitary, communal nesting can occur during colder months for thermoregulation. Communication primarily involves olfactory cues, including urine marking and pheromones, critical for territoriality and reproduction. Their diet is omnivorous, consisting of seeds, nuts, fruits, insects, and fungi, which they often cache. Of major concern, deer mice are the primary reservoir for Sin Nombre hantavirus (SNV) – a zoonotic pathogen shed in their urine, feces, and saliva. The virus becomes aerosolized when contaminated materials are disturbed, posing a significant public health risk, particularly for individuals in close proximity to infested areas.