International Journal of Comparative Psychology

The

temporal characteristics of grooming in an open field were studied in rats from two different genotypes (NR, brown Norway rats bred from an original wild stock and KM, Krushinsky-Molodkina albino rats selectively bred for audiogenic seizure susceptibility). The measures of grooming recorded were time of onset of any grooming activity, duration and number of grooming episodes and total time spent grooming during successive 3-min intervals over a total 12-min period. The results demonstrated that grooming episodes of different durations displayed different features across the course the test. Grooming was minimal in the first minutes of the test and the longest grooming episodes were observed after the sixth minute in most of the rats. The number and proportion of prolonged episodes (over 21 s in duration)increased over time. Short-duration episodes (1-3 s) were not connected with the specific stage of the test and/or the decrease in locomotion. The scores of grooming duration were higher in NR in comparison to the KM rats. No significant effects were found for strain and sex for total numbers of grooming episodes.