A new research has unveiled that grandmothers have played a vital role in the developing the pair bonds and also, it has led to the development of behaviour among men to protect his female partner from competition. Kristen Hawkes, an anthropologist at University of Utah, said this has developed monogamous relationships.

In fact, the researchers have termed grandmothers to be the key to human evolution. The researchers have taken the help of computer simulations to show that it leads to more number of older, fertile males. The research also shows as to why women prefer long-term relationship with older women.

The researchers have explained that grandmothers take care of children giving more time to mothers to indulge in romantic relationships. Also, this ways the mother can have more children as the grandmother is already taking care of the kids.

“Mortality is higher in men than women too, but that difference is more than overwhelmed by fertility continuing in old men. Mate guarding is found in other animals when mating sex ratios are male-biased”, said Hawkes.

Hawkes has affirmed the explaination continues to be the same that when there are more number of competitors then males perform better to protect current mate rather than looking out for new partners.

With time, the number of older male increased who looked for younger females. They were more likely to leave descendants.