Behavioral evaluation of laboratory-housed ferrets (Mustela putorius furo) in different enclosure sizes

The domestic ferret ( Mustela putorius furo ) is a common research model for infectious disease and behavioral studies. Ferrets are social animals that are commonly pair-housed. The United States has no species-specific regulatory standards forhousing ferrets. Optimal enclosure dimensions have also not been investigated in this species, and cage sizes reported in theliterature vary. Adequate space is an important animal welfare consideration, as smaller cages have been linked to increasedincidence of stress- or boredom-related behaviors in some species. Here, we evaluated activity budget and space utilization in 2 different enclosure sizes for pair-housed female ferrets ( n = 12). Single cages measured 78.7 × 78.7 × 45.7 cm; double cages were comprised of 2 single cages connected by a short tunnel measuring 17.8 cm. Three pairs of ferrets were housed in each cage size and continuous video recordings were captured for 2 wk prior to crossover to the other cage size. The overall activitybudget was similar between groups, with the predominant behavior being inactivity (89%). Stereotypic behaviors, such ascage biting or escape attempts, were infrequent (< 0.1%) in both groups. Ferrets in double cages remained in the same cageas their partner 96% of the time, suggesting that social support is very valuable. Our results suggest that ferrets in both cagesizes experienced satisfactory welfare conditions. Our findings also suggest that while cage size is not the only determinantof conspecific aggression, larger cages may be an effective intervention to ameliorate aggression in certain ferrets based on signalment or behavioral history, with particular utility as a potential alternative to re-pairing or single-housing. This study provides valuable information to guide animal care and use programs regarding appropriate ferret housing.