Social factors, not just genes, influence the reproductive fitness of female dolphins, an international team of behavioral scientists found on Tuesday.

Dolphins [File photo]

Dr Celine Frere, who led the research at the University of New South Wales, in Sydney of Australia, studied how inherited genetic characteristics and social factors influenced the reproductive success of a group of bottle nose dolphins in Shark Bay, Western Australia.

She said that good genes are only part of the picture; and that an individual's social network has a strong influence on reproduction.

The team used calving success, where the offspring survive infancy (past three years of age), in their measurement.

"We found that genetic effects only account for 16 percent of variation in calving success amongst the female dolphins, whereas social factors are a much stronger determining factor - they are almost three times as important as having good genes," Frere told ABC News on Tuesday.

In a paper published in this week's Proceedings of the National Academy of Sciences, the researchers analyzed twenty-five years of observational data from 52 female dolphins which detailed the number of offspring, and whom they associated with.

This information was combined with DNA results to establish how closely related the dolphins in the group were.

No one knows exactly why having friends and relatives who have done a good job having babies helps, bur Frere noted that " Dolphins in this population are attacked by sharks, so protection by other females may help reproduction."

Frere said she planned to apply the technique to the Eastern Water Dragon, an Australian lizard that is "socially complicated" like dolphins, but easier to study because it does not live underwater.