Environmental enrichment delays the development of stereotypic behavior and reduces variability in behavioral experiments using California mice (Peromyscus californicus)

Abstract

Domesticated mice and rats have shown to be powerful model systems for biomedical research, but there are cases in which the biology of species is a poor match for the hypotheses under study. The California mouse (Peromyscus californicus) has unique physiological and behavioral traits and has emerged as a powerful model for studying sex differences in the biology of psychiatric disease, which is particularly relevant considering the new NIH guidelines that require the inclusion of sex as a biological variable. Despite its growing role in preclinical research, there is a lack of studies assessing species-specific housing needs, which presents a challenge for research facilities seeking to ensure good welfare and obtaining high-quality experimental data. Indeed, captive California mice present a high prevalence of stereotypic backflipping behavior, a common consequence of suboptimal housing and a potential source of experimental outcome variability. Using three different cage systems, the present studies show that increasing housing space as well as social and environmental complexity can delay the development of stereotypic behavior in male and female California mice. Critically, this reduction in stereotypy is accompanied by increased effect sizes of stress in an established model for social anxiety. These results suggest that increased cage size and enrichment could enhance welfare in California mice while simultaneously increasing the quality of behavioral experiments.

Transmission of paternal retrieval behavior from fathers to sons in a biparental rodent

“…Since housing was standardized across the groups, and males were assigned to the paternal retrieval experience randomly, it is unlikely that there are selection or environmental effects. In California mice males, flipping behavior has been shown to increase with age (Minie et al., 2021) which could be a potentially confounding variable in the current study. An alternative theory is that stereotypies serve separate functions across species, and in some may be associated with impaired behavioral inhibition (Novak et al., 2016).…”

“…Stereotypies are inflexible, repetitive patterns of behavior that have no obvious goal or function. They have been hypothesized to reflect poor welfare (Mason & Latham, 2004; Minie et al., 2021), but may also be more broadly indicative of a more anxious or stressed state. HPR males demonstrated more flips during both undisturbed observation and in response to pup displacement than RPR males.…”

Exploring the Importance of Environmental Complexity for Newly Hatched Zebrafish

“…The significance of keeping laboratory animals in adequate environmental conditions extends beyond the welfare considerations of laboratory animals; it also holds implications for the quality and reliability of research outcomes. Enriched environments have the potential to yield more robust and reproducible experimental results, as stressed or unhealthy animals may not respond predictably to experimental treatments [20][21][22].…”