Humans are known for their competitive nature regardless of their sex. There is apparently something exclusive to females though: they, as do other mammals, might be vying with each other by giving birth to bigger babies, according to scientists from the University of Exeter. The paper is published in the journal Scientific Reports.
Competing to have the most surviving offspring has long since been thought to fuel evolution. The findings of the study that lasted for 13 years indicate that this behaviour might be extended to life growing in the mother’s body.
Female mongooses were found to produce bigger pups as a response to competition when the team of researchers used ultrasound scans to investigate prenatal investment. Can competition among individuals of a population start in the womb? This concept remains a bone of contention among scientists, but the authors of the new study write that their results are evidence that competition among females begins before the birth of their offspring.
The data suggests that social mammals (that would include humans as well) might affect womb conditions to boost their reproductive success. In this way, females would be ‘preparing’ their young so that the latter can deal with competition after birth – the training starts even before the child is born. But why?
Female mongooses live in groups and give birth at the same time. This prevents them from identifying their own offspring, and they are thus unable to assist them in the face of competition with other babies. To counter this predicament, responding to competition, the mothers would then invest more resources directed at their womb to ‘build’ offspring that can withstand the pressure of competition once it is born; the more females breeding at the same time, the bigger their foetuses would turn out to be. Furthermore, the size would be more pronounced under conditions that drive competition further such as low rainfall and low weight of the mother.
How do the baby mongooses grow bigger? The scientists do not yet know whether it is the result of the mothers eating more food or whether their stored body fat is being used to do so.