Associations between husbandry conditions, human-animal interactions and animal behavior in pet rats – An exploratory study

Reports examining how housing conditions, environmental enrichment, and human–animal interactions affect the behavior and welfare of pet rats ( Rattus norvegicus domestica ) remain relatively scarce in scientific literature. Most research focuses on standardized laboratory housing, which may not fully reflect the diverse environments, social conditions, and human–animal relationships in private homes. For this reason, this study examined relationships between husbandry practices and various behavioral outcomes through an online survey among German-speaking rat caretakers. Principal component analyses were conducted to summarize items and derive behavioral factors. Then, predictors of “Exploratory Behavior & Cautious Responses During Free Roaming”, “Potential Behavioral Indicators of Welfare”, “Repetitive Behavior”, “Agonistic Behavior”, and “Socio-positive Behavior” were examined using linear and logistic regression models. Offering paper-based enrichment materials in the home-enclosure, a younger age, and more frequent opportunities to roam outside the enclosure were positively associated with “Exploratory Behavior & Cautious Responses During Free Roaming” (β = 0.16, p = 0.001, β = −0.14, p = 0.002, and β = 0.15, p = 0.001, respectively; N = 467). In the regression model for “Potential Behavioral Indicators of Welfare” (N = 469) (including bruxing, eye-boggling, and self-grooming), behaviors were most strongly predicted by a rat’s age (β = 0.18, p < 0.001), followed by frequencies of positive human–animal interactions (β = 0.16, p < 0.001), the duration of direct engagement with the caretaker (β = 0.10, p = 0.026), and providing enrichment items such as dog toys, cat toys, or a food ball (β = 0.10, p = 0.031). Providing rats with a salt lick stone, mineral stone, and/or hay in a hay rack was associated with less bruxing, eye-boggling, and self-grooming (β = –0.10, p = 0.022). The model for “Repetitive Behavior” (N = 480) was not significant (p = 0.053). Social behavior was associated with group size, age, caretaker engagement, and paper-based enrichment. Rats kept in smaller groups, as well as younger rats, showed more “Agonistic Behavior” (β = –0.13, p = 0.005; β = –0.12, p = 0.009; N = 443). “Socio-positive Behavior” towards conspecifics was more common when caretakers spent more time interacting with their rats and provided paper-based enrichment more frequently (β = 0.13, p = 0.005, and β = 0.11, p = 0.022; N = 443). Overall, the findings highlight the importance of environmental complexity, species-appropriate enrichment, adequate social housing, and regular positive human contact for ensuring welfare in pet rats.