Intensive longitudinal characterization of multidimensional biobehavioral dynamics in laboratory rats

Rats have been used as animal models for human diseases for more than a century, yet a systematic understanding of basal biobehavioral phenotypes of laboratory rats is still missing. In this study, we utilize wireless tracking technology and videography, collect and analyze more than 130 billion data points to fill this gap, and characterize the evolution of behavior and physiology of group-housed male and female rats (n = 114) of the most commonly used strains (Lister Hooded, Long-Evans, Sprague-Dawley, and Wistar) throughout their development. The resulting intensive longitudinal data suggest the existence of strain and sex differences and bi-stable developmental states. Under standard laboratory 12-h light/12-h dark conditions, our study found the presence of multiple oscillations such as circatidal-like rhythms in locomotor activity. The overall findings further suggest that frequent movement along cage walls or thigmotaxic activity may be a physical feature of motion in constrained spaces, critically affecting the interpretation of basal behavior of rats in cages. [Display omitted] •Bistable evolution of rat behavior during development and depends on sex and strain•Big data analysis reveals circatidal-like rhythms in locomotor activity•Thigmotaxic behavior in home-cage may be driven by random walk and not stress Hasanpour et al. reveal sex and strain dependency of temporal evolution of behavior of group-housed rats from childhood to adulthood. By collecting and analyzing billions of data points obtained from continuous, wireless monitoring, they further found significant circatidal-like rhythms in locomotor activity that are common in coastal, but not terrestrial, animals.