Laterality of suckling behaviour in three zebra species

Abstract

Although side preference while suckling is an easily characterised lateralised behaviour, few studies have been conducted. We observed laterality in suckling behaviour in three captive zebra species to test two hypotheses: laterality affected by the foal (motor laterality) and laterality affected by the mother. In total we observed 35 foals of Grevy's, plains, and mountain zebra in two zoos and recorded 5128 successful suckling bouts and 9095 unsuccessful suckling attempts. At the population level the only factor affecting side preference of suckling bouts and attempts was the identity of the individual foal. Ten foals showed individual preferences: seven foals preferred suckling from the left side of the mother, three preferred suckling from the right side of the mother. The individual preferences increased with increasing age of the foal. Only one foal was refused more often from the opposite side than the preferred side used for suckling whereas three other foals were refused from the preferred side. Foals that preferred suckling either from left or right side were refused by the mare more often than foals which showed non-preference. Thus lateral preferences in suckling behaviour of zebra foals seem to be in line with the motor laterality hypotheses.

The Many Axes of Deer Lactation

“…This greater milk production by the left teats seems consistent both at the individual and population level, and agree with the preferential suckling from the left side previously observed in monkeys, whales and equids [16][17][18][19][20][21], suggesting a possible connection. However, these side preferences cannot be directly linked to nipple preference since it can also be related to motor lateralization [20,21]. These axial differences in milk production and composition may be mediated by the effect of prolactin [33] and Fig.…”

“…Thereafter it was found that sperm whales also favoured suckling from the left side [19]. The same case was seen in zebra foals [20] and horses [21] as well, but these left-side preferences have been explained as motor-related due to the fact that all nipples can be reached from both sides. Nevertheless, this repeated pattern is surprising, and deserves further study as it suggests the possibility of differential milk production being biased to a preferred side.…”