Previous explanations of the phenomenon of birth synchronicity have suggested that having offspring at the same time might offer an advantage through a decreased risk of predation or allowing more efficient communal care. However, the new research, conducted by Dr Sarah Hodge and Dr Michael Cant (a Royal Society University Research Fellow) – both of the University of Exeter’s Centre for Ecology and Conservation – and Dr Matthew Bell of the University of Cambridge’s Department of Zoology, proposes that synchronised births may owe more to competition between different females’ offspring than any other factor.
The authors point out that infanticide – a relatively common occurrence in mongoose groups – is perpetrated much more frequently by females that have not given birth themselves (even though they may be pregnant). Through observations of mongoose groups in the wild, they discovered that the offspring of mongoose mothers who gave birth significantly before the rest of their cohort stood a much higher chance of being killed by a jealous mongoose mother-to-be.
One might think that the solution to this would be to give birth after the rest of the group – but the scientists discovered that this results in offspring who are considerably smaller and weaker than the rest of their group and are therefore likely to lose out in competition for limited resources. As such, it appears that mongooses have evolved extreme birth synchronicity in order to find the ideal middle way between these two problems.