Hae

<p>Working animals spend hours each day in close contact with humans and require training to understand commands and fulfil specific tasks. However, factors driving cooperation between humans and animals are still unclear, ...

<p>Grandmothers play a crucial role in families enhancing grandchild wellbeing and survival but their effects can be context-dependent, and the children born in poor conditions are most likely to benefit from the investments made by helping grandmothers. In this study, we examined, for the first time, whether grandmothers' presence modified associations between adverse birth status and survival up to 5 years of age. In detail, we verified, whether (i) firstborns, (ii) twins, (iii) children born within 24 months after their sibling, and (iv) children followed by short interval (i.e. their younger sibling was born within 24 months) survived better when either their maternal, paternal, or both grandmothers were present. Moreover, we evaluated whether illegitimate children survived better when the maternal grandmother was present. We used an extensive and largely pre-industrial demographic dataset collected from parish population registers kept by the Lutheran Church of Finland from years 1730–1895. We show that although grandmother presence cannot mitigate adverse effects of many poorer birth conditions, grandchildren whose next sibling was born after a short interval survived better when the maternal grandmother was present. Taken together, these findings highlight an important role of grandmothers in compensating the mother's investment in the new baby, thus enabling overall faster successful reproductive rate of mothers. Whilst the opportunity for grandmothers to mitigate the risks of adverse birth statuses is limited, this study does show - through the beneficial effect on survival for those with a short subsequent birth interval - that grandmothers can increase their daughters' and their own reproductive success.</p>...

<p><br></p><p>Background</p><p>Many environmental factors are known to hinder breastfeeding, yet the role of the family living environment in this regard is still poorly understood.</p><p>Objectives</p><p>Therefore, we ...

Although senescence is often observed in the wild, its underlying mechanistic causes can rarely be studied alongside its consequences, because data on health, molecular and physiological measures of senescence are rare. ...

<p><br></p><p>Although social behaviour is common in group-living mammals, our understanding of its mechanisms in long-lived animals is largely based on studies in human and non-human primates. There are health and fitness ...

<p>Parental self-efficacy (PSE), a measure of the subjective competence in the parental role, has been linked with child well-being and health. Research on the influence of PSE on child eating habits is scarce, and the few ...

<p>A good quality diet in childhood is important for optimal growth as well as for long-term health. It is not well established how eating behaviors affect overall diet quality in childhood. Moreover, very few studies have ...

<p>Help is directed towards kin in many cooperative species, but its nature and intensity can vary by context. Humans are one of few species in which grandmothers invest in grandchildren, and this may have served as an ...

<ol start="1"><li>Many mammals grow up with siblings, and interactions between them can influence offspring phenotype and fitness. Among these interactions, sibling competition between different-age offspring should lead to reproductive and survival costs on the younger sibling, while sibling cooperation should improve younger sibling's reproductive potential and survival. However, little is known about the consequences of sibling effects on younger offspring life-history trajectory, especially in long-lived mammals.<br><br></li><li>We take advantage of a large, multigenerational demographic dataset from semi-captive Asian elephants to investigate how the presence and sex of elder siblings influence the sex, survival until 5 years old, body condition, reproductive success (i.e. age at first reproduction and lifetime reproductive success) and long-term survival of subsequent offspring.<br><br></li><li>We find that elder siblings have heterogeneous effects on subsequent offspring life-history traits depending on their presence, their sex and the sex of the subsequent offspring (named focal calf).<br><br></li><li>Overall, the presence of an elder sibling (either sex) strongly increased focal calf long-term survival (either sex) compared to sibling absence. However, elder sisters had higher impact on the focal sibling than elder brothers. Focal females born after a female display higher long-term survival, and decreased age at first reproduction when raised together with an elder sister rather than a brother. Focal males born after a female rather than a male showed lower survival but higher body weight when both were raised together. We did not detect any sibling effects on the sex of the focal calf sex, survival until 5 years old and lifetime reproductive success.<br>​​​​​​​<br></li><li>Our results highlight the general complexity of sibling effects, but broadly that elder siblings can influence the life-history trajectory of subsequent offspring. We also stress the importance of considering all life stages when evaluating sibling effects on life trajectories.</li></ol>...

<p>Frequent social interactions, proximity to conspecifics, and group density are main drivers of infections and parasite transmissions. However, recent theoretical and empirical studies suggest that the health benefits ...