The effect of a mother's rank on her offspring's pre-weaning rank in farmed red deer

Abstract

Maternal rank “inheritance” occurs in cercopithecine primates, spotted hyenas and several ungulates. A recently observed positive relationship between dominance rank of a mother and that of her sub-adult offspring in wild red deer ( Cervus elaphus) suggests that maternal rank “inheritance” also occurs in this species. This may be caused by various factors. We have focused on one of them. Presuming that an offspring will “inherit” the dominance rank of its mother, we hypothesized that the mother will support her offspring by directing attacks towards the peers of her offspring. We observed three groups of hinds and calves (hinds/calves n = 18/7, 18/10 and 28/14, respectively). Observation took place since the 3rd month up to the 11th month of the calves’ age. We recorded 8339 agonistic encounters. The rank of an animal was assessed by its fighting success. The fighting success of the offspring increased with the fighting success of its mother (GLMM, F (1,31) = 29.88, P = 0.0001) and with the offspring's birth body weight (GLMM, F (1,31) = 22.72, P = 0.0001). Milk hinds (females with a surviving calf) attacked other calves more often than the yeld hinds (females without a calf) did. The aggressiveness of the milk hinds increased with the aggressiveness of the attacked calves (GLMM, F (2,164) = 11.68, P = 0.0001). Although we observed several events when a mother intervened on behalf of her offspring, it seems that mothers affected the rank of their offspring rather indirectly by the offspring's birth body weight, timing of delivery, etc.