Data from: No apparent benefits of allonursing for recipient offspring and mothers in the cooperatively breeding meerkat

1. Cooperative behaviours by definition are those that provide some
benefit to another individual. Allonursing, the nursing of non-descendent
young, is often considered a cooperative behaviour and is assumed to
provide benefits to recipient offspring in terms of growth and survival,
and to their mothers, by enabling them to share the lactation load.
However, these proposed benefits are not well understood, in part because
maternal and litter traits and other ecological and social variables are
not independent of one another, making patterns hard to discern using
standard univariate analyses. 2. Here, we investigate the potential
benefits of allonursing in the cooperatively breeding Kalahari meerkat,
where socially subordinate females allonurse the young of a dominant pair
without having young of their own. 3. We use structural equation modelling
to allow us to account for the interdependence of maternal traits, litter
traits and environmental factors. 4. We find no evidence that allonursing
provides benefits to pups or mothers. Pups that received allonursing were
not heavier at emergence and did not have a higher survival rate than pups
that did not receive allonursing. Mothers whose litters were allonursed
were not in better physical condition, did not reconceive faster and did
not reduce their own nursing investment compared to mothers who nursed
their litters alone. These patterns were not significantly influenced by
whether mothers were in relatively good, or poor, condition. 5. We suggest
that allonursing may persist in this species because the costs to
allonurses may be low. Alternatively, allonursing may confer other, more
cryptic, benefits to pups or allonurses, such as immunological or social
benefits.