Brain size and fertility in mammals has connection with parental care

A recent study reveals that brain size in mammals is associated with paternal care. The study published in the journal Behavioural Ecology and Sociobiology suggests that larger offspring brain is connected with amount of paternal care and higher fertility which is connected with additional support from individuals other than the offspring’s biological parents (alloparents).

The research team compared data from 478 mammal species. The findings checked for effects of energy from care givers based on brain size and fertility. The range of mammals tested for experiment included mice, meerkats, moneys, apes and lions.

A brain hypothesis confirmed that brain size develops with increased additional energy available in females which is predictable and constant from help with looking after offspring. Dr Sandra Heldstab who is a corresponding author on the study reported in a statement, “Both reproduction and brain tissue are energetically very expensive, and one way for females to reduce their cost is by distributing that cost over other individuals by sharing the burden of care. Unlike previous studies, we distinguished between paternal and alloparental care because we expected there to be a difference between how reliable they are and in the effect they may have on brain size and fertility.”

The research team made comparisons with evolution of human brain for the study.  Humans differs from mammals in brain size, body size and high reproductive output. Reports suggest that multi-family cooperative parenting involved a stable and reliable care from both the parents and biological parents. It was a key point in determining the brain size of mammals and its association with parental care.

Dr Sandra Heldstab concludes: “Paternal care is both reliable and stable; therefore we’d expect it to be associated with brain size. Additional care from individuals who are not the offspring’s parents often fluctuates as they adjust their caring effort depending on both food availability and their own reproductive needs. This unpredictable type of care doesn’t provide enough stable energy to affect brain size, but our findings suggest that the additional energy it does provide is associated with a significant increase in fertility, as females readily respond through litter size adjustments to variable amounts of energy inputs.”