Factors predicting the frequency, likelihood and duration of allonursing in the cooperatively breeding meerkat

Allolactation, the nursing of another female’s offspring, occurs most commonly where several females raise young simultaneously in the same nest, but also occurs in singular breeders where non-breeders also lactate for the offspring of dominant females. In this study, we investigate the factors predicting the frequency of allonursing, whether or not subordinate female meerkats invest in allonursing, and how much time they invest. Around half of all litters born to dominant females were allonursed. Litters born later were more likely to be allonursed than those born early in the season. Group size, litter size, rainfall, and maternal condition were not associated with the likelihood that a litter was allonursed. Subordinate females were more likely to allolactate if they were (or had recently been) pregnant. This effect was stronger if they were also highly related to the litter’s mother, suggesting that females may gain indirect benefits from allolactating. Older females and those that had recently returned to the group following eviction were also more likely to allolactate. Females nursed for longer periods if they were in good condition, and invested more time if the litter was large or if the litter mother was in poor condition. We suggest that allolactation generates a combination of direct and indirect benefits