Den use and heterothermy during winter in free-living, suburban striped skunks

Many mammals use heterothermy to meet challenges of reduced food availability and low temperatures, but little is known about the prevalence of heterothermy in wild mesocarnivores. We monitored body temperature (T_b) in free-living striped skunks (Mephitis mephitis) through winter 2015–2016 in suburban Flagstaff, Arizona, a high-elevation site that experiences temperate winters. Subcutaneous T_b and heterothermy index (HI) were significantly affected by ambient temperature, and varied significantly across 7 skunks in midwinter. Twenty-one of 36 (58%) unique diurnal dens used by skunks were associated with human structures, and although females were found in dens under houses more than expected compared to males, we found little evidence that skunks selected dens where they could access anthropogenic heat sources. This is the 1st study to document T_b variation over winter in free-living striped skunks. Our results are consistent with 2 previous studies of captive skunks in documenting considerable variation among individuals in the extent of heterothermy. If reduced T_b during heterothermy alters rate of viral replication, variation among individual skunks could have implications for the maintenance and spread of diseases like rabies.