Modeling the influence of morphology on the movement ecology of groups of infant rats (Rattus norvegicus)

Abstract

Body morphology appears to strongly determine the behavior of infant rats in an arena (May et al., 2006). In this article, we systematically examined the influence of body-flexibility on the group behavior of infant rats (Rattus norvegicus) by comparing one-, two-, and three-segmented simulated rats with 7- and 10-day-old rats in an arena. Simulated rats provided very different fits to 7-day-old rat pups compared with 10-day-old pups. With respect to 7-day-old pups, three-segmented rats were similar on 83% of our metrics, two-segmented rats were similar on 33% of our metrics, and one-segmented rats were similar on 66% of our metrics. Both one- and three-segmented simulated agents matched 7-day-old rats better than two-segment agents, but it is still premature to conclude which of the three simulated agents best matched the 7-day-old rats. However, no group of simulated rats was similar to 10-day-old pups on any metric. Our results suggest that morphology strongly determines behavior in groups of 7-day-old rats, but that other mechanisms, from more active intersegment control to more influential top-down control, are required to explain the group behavior of 10-day-old rats.