By BEN CLERKIN

Last updated at 19:55 23 December 2007

Father Christmas gets all the publicity but it's mothers who really keep the season together, a survey has revealed.

The maternal side of any family apparently makes twice as much effort to keep in touch as the male line.

Which is why there will be more of mother's family - her parents and grandparents - round the table tomorrow lunchtime than father's.

Maternal family members are much more willing to travel further than paternal relatives to see their nearest and dearest, a study has discovered.

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Family members related through their mothers matter more to each other than those related through their fathers, and not just at this time of year.

They are twice as likely to see their family every day or a few times a week.

The reason is thought to be based on human evolution because throughout history men could never be certain that they were the biological father.

So maternal grandparents were always more certain than paternal grandparents that a grandchild was related to them. And maternal grandparents, especially maternal grandmothers, will go the extra mile to visit their family.

Thomas Pollet and colleagues at Newcastle University and a group of researchers at the University of Antwerp, Belgium, investigated how far maternal grandparents and paternal grandparents will go to maintain face-to-face contact with their grandchildren.

Mr Pollet said: "As the festive period approaches, many people will be making the effort to ensure they meet up - and we've found that's particularly important if family members are related through mothers.

"Even in families where there has been divorce, we found consistent differences - grandparents on your mother's side make the extra effort.

"Throughout history, women are always related by maternity whereas men can never be wholly certain they are the biological father to their children."

The study found that more than 30 per cent of maternal grandmothers who live with 19 miles of their grandchildren see them at least a few times every week.

About 25 per cent of maternal grandfathers kept up the same level of contact.

But only around 15 per cent of the paternal grandmothers and grandfathers saw their grandchildren daily or several times a week.

The research, which is published in the latest edition of the journal Evolutionary Psychology, was conducted on a sample of 800 grandparents.

• The average family will fall out by mid-morning on Christmas Day, according to a study.

Even before the turkey, the Queen's Speech and a heated game of charades the typical British family will have its first argument at 10.13am.

The next will happen at 12.42pm when children moaning about receiving the wrong presents will feel the wrath of stressed-out parents.

Eventually mother and father will argue between 1pm and 3pm because she's overwrought from cooking and he's "merry", according to a survey for Travelodge.