Spatial position relative to group members affects weight gain in meerkats ( Suricata suricatta )

Social animals often face a trade-off between the costs of foraging competition among group members and the benefits of protection from predators offered by group living. The spatial position of an individual in relation to the other group members during foraging can mediate the effects of this trade-off as individuals at the front or edge may have better access to food resources, but also higher predation risk than individuals near the centre of the group. Using meerkats (Suricata suricatta) as a model species, we investigated the effect of individual spatial position within a group on foraging success. We determined the spatial position of individuals in a meerkat group by fitting the animals with high-resolution GPS loggers. As a proxy of foraging success, we used meerkats’ individual body weight differences between the start and the end of daily data collection over foraging periods (3 hours). We found significant individual differences in meerkats’ spatial positions within the group. In addition, age-dependent differences in spatial position became obvious, with younger individuals spending more time in the centre of the group and less time in the front. However, younger individuals who spent more time on the side of the group relative to older individuals had higher daily weight gain, indicating more successful foraging. In older individuals, we found that the dominant females tended to spend more time towards the front of the group, but gained less weight in this location, contrary to the predicted association between front edge of the group and better access to food resources. Our results suggest that the relationship between weight gain and spatial position is highly nuanced and likely dependent on more than just trade-offs between foraging success and predation risk.