Behavioral adaptation in an adoptive free-ranging female Tibetan macaque.

Adoption is an important form of allomaternal care in nonhuman primates, with implications for reproductive output and infant survival. Here, we report a kidnapping that became an adoption of a 3-week-old infant by a mother with her own infant in Tibetan macaques (Macaca thibetana). The adoptive mother nursed her "new" infant (allonursing), the first observation of this behavior in the species. The case provided a natural experiment for comparing how a female copes with a heavier burden of care for both her biological infant and another female's infant, compared to mothers caring for only one infant. Our results showed that the adoptive female spent more time foraging and resting, and less time in group social activity compared to females with a single infant. The adoptive female showed more instances of social bridging. Although the duration of post-bridging grooming received from group members decreased, the frequency of such grooming increased. We discuss this adoption with reference to possible factors involved in the evolution of adoption and allonursing behavior in Tibetan macaques.

A milk-sharing economy allows placental mammals to overcome their metabolic limits.

SignificanceHere, we demonstrate that a naturally evolving behavior (allonursing) has greater effect on reproductive power (mass per unit of time) and output (litter mass at birth) than does artificial selection (domestication). Additionally, we demonstrate the importance of resource optimization afforded by sociality (rather than resource abundance per se) in shaping a species' life history profile and its ability to overcome its own physiological constraints.

Getting fat or getting help? How female mammals cope with energetic constraints on reproduction.

BACKGROUND: Fat deposits enable a female mammal to bear the energy costs of offspring production and thus greatly influence her reproductive success. However, increasing locomotor costs and reduced agility counterbalance the fitness benefits of storing body fat. In species where costs of reproduction are distributed over other individuals such as fathers or non-breeding group members, reproductive females might therefore benefit from storing less energy in the form of body fat. RESULTS: Using a phylogenetic comparative approach on a sample of 87 mammalian species, and controlling for possible confounding variables, we found that reproductive females of species with allomaternal care exhibit reduced annual variation in body mass (estimated as CV body mass), which is a good proxy for the tendency to store body fat. Differential analyses of care behaviours such as allonursing or provisioning corroborated an energetic interpretation of this finding. The presumably most energy-intensive form of allomaternal care, provisioning of the young, had the strongest effect on CV body mass. In contrast, allonursing, which involves no additional influx of energy but distributes maternal help across different mothers, was not correlated with CV body mass. CONCLUSIONS: Our results suggest that reproducing females in species with allomaternal care can afford to reduce reliance on fat reserves because of the helpers' energetic contribution towards offspring rearing.

Effect of nursing behavior, sex of the calf, and parity order on milk production of buffaloes / Efecto del comportamiento de amamantamiento, sexo del becerro y orden del parto sobre la producción de leche en búfalos / Efeito do comportamento de amamentação, sexo do bezerro e ordem de parto sobre a produção de leite em bubalinos

Summary Background: the allonursing effect on daily milk production (DMP) and total milk production (TMP) has been little explored. Objective: to evaluate the effect of nursing behavior, sex of the calf and parity order (PO) on DMP and TMP of buffalo cows. Methods: 35 buffalo cows and their calves were evaluated. Observations were performed monthly (three consecutive days) from May to November. The nursing behavior was characterized as: 1) Isolated filial nursing (IFN); 2) Collective filial nursing (CFN), and 3) Non-filial nursing (NFN). Cows were grouped into four categories to study the effects of nursing behavior on DMP and TMP: 1) Non-permissive (NP); 2) Filial permissive (FP); 3) Filial and collective filial permissive (FCFP); and 4) Filial, collective filial and non-filial permissive (FCFNFP). DMP was recorded three days per month and TMP was calculated as DMP*270 days of lactation. Results: sex of the calf and second and third PO had an effect on nursing behavior (p<0.05). DMP and TMP were significantly affected by calf sex and nursing behavior (p<0.05). PO had no effect on DMP and TMP. Conclusion: our results suggest that nursing behavior is associated with milk production in buffalo cows. Buffalo cows that accept all types of nursing behavior were had the highest DMP and TMP. Sex of the calf influenced nursing behavior, DMP, and TMP, so that buffalo cows with male calves displayed more frequent allonursing behavior and yielded more milk.

Resumen Antecedentes: el comportamiento del alo-amamantamiento sobre la producción diaria de leche (DMP) y producción total de leche (TMP) ha sido poco explorado. Objetivo: evaluar el efecto del comportamiento de amamantamiento, el sexo del becerro y el orden de parto (PO) en la DMP y TMP de bufalas. Métodos: se evaluaron 35 hembras bufalinas y sus crías. Las observaciones se realizaron mensualmente (durante tres días consecutivos) entre mayo y noviembre. El comportamiento de amamantamiento se caracterizó como: 1) Amamantamiento filial aislado (IFN); 2) Amamantamiento filial colectivo (CFN) y 3) Amamantamiento no filial (NFN). Para evaluar los efectos del comportamiento de amamantamiento en la DMP y TMP, las vacas fueron agrupadas en 4 categorías: 1) No permisivas (NP); 2) Permisiva filial (FP); 3) Permisiva filial y colectiva filial (FCFP) y 4) Permisiva filial, colectiva filial y no colectiva (FCFNFP). La DMP se registró tres días por mes, y la TMP fue calculada como DMP*270 días de lactancia. Resultados: el sexo del becerro, el segundo y tercer PO tuvieron efecto sobre el comportamiento de amamantamiento (p<0.05). La DMP y la TMP se afectaron significativamente por el sexo del becerro y el comportamiento de amamantamiento (p<0.05). El PO no tuvo efecto sobre la DMP y la TMP. Conclusiones: nuestros resultados sugieren que el comportamiento de amamantamiento está asociado a la producción de leche en vacas bubalinas. Las bufalas permisivas a todo tipo de amamantamiento presentaron mayor DMP y TMP. El sexo del becerro influyó en el comportamiento de amamantamiento, en la DMP y en la TMP. Las bufalas con becerro macho presentaron comportamiento de alo-amamantamiento más frecuente y produjeron mayor cantidad de leche.

Resumo Antecedentes: o comportamento de alo-amamentação sobre a produção de leite diária (DMP) e produção de leite total (TMP) tem sido pouco explorado. Objetivo: avaliar o efeito do comportamento de amamentação, sexo dos bezerros e ordem de parto (PO) na DMP e TMP em vacas bubalinas. Métodos: trinta e cinco fêmeas e suas crias foram avaliadas no estudo. As observações foram realizadas mensalmente (três dias consecutivos) de maio a novembro. O comportamento de amamentação foi caracterizado como 1) amamentação filial isolada (IFN); 2) amamentação coletiva filial (CFN) e 3) amamentação não filial (NFN). Para avaliar os efeitos do comportamento da amamentação na DMP e TMP, as vacas bubalinas foram agrupadas em 4 categorias: 1) não permissiva (NP); 2) permissiva filial (FP); 3) permissiva filial e coletiva filial (FCFP) e 4) permissiva filial, coletiva filial e não filial (FCFNFP). A DMP foi registrada três dias para cada mês e a TMP foi calculada como DMP*270 dias de lactação. Resultados: o sexo dos bezerros, a segunda e terceira PO tiveram efeitos no comportamento de amamentação (p<0.05). A DMP e TMP foram significativamente afetadas pelo sexo dos bezerros e comportamento de amamentação (p<0.05). A PO não teve efeito na DMP e TMP. Conclusões: nossos resultados sugerem que o comportamento de amamentação estão associados a produção de leite em vacas bubalinas. As vacas bubalinas que são permissíveis a todos os tipos de amamentações foram aquelas com maior DMP e TMP. O sexo dos bezerros influenciou o comportamento de amamentação, DMP e TMP, sendo que as vacas bubalinas que possuem bezerros machos apresentaram frequente comportamento de alo-amamentação e produziram maiores quantidades de leite.

No apparent benefits of allonursing for recipient offspring and mothers in the cooperatively breeding meerkat.

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. 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. We use structural equation modelling to allow us to account for the interdependence of maternal traits, litter traits and environmental factors. 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. 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.