Why can't a man be more like a prairie vole?
When a prairie vole, a furry sort of Midwest rodent, becomes a father, he doesn't seem put off by the fact that he can't breast-feed. He isn't filled with conflict and doubt over his role. He doesn't seem to harbor any ambivalence about whether the litter is really his.
In fact, scientists say he and the mother prairie vole constitute a "breeding partnership" for most of their months-long life.
"Male prairie voles spend equal amounts of time caring for offspring, keeping them warm, huddling over them, retrieving them. Male and female partners tend to share the parental duties, so the female doesn't leave the nest to forage for food unless the male is there," said Melinda Novak, a behavioral scientist at the University of Massachusetts at Amherst.
If he were a man, he would probably do dishes. And laundry.
Human fathers, of course, have become the subject of alarm as social scientists and the general public blame widespread social problems on their increasing absence from their children. Due mostly to divorce and single childbearing, more than a third of all children in the U.S. live without their fathers, up from 17% in 1960.
According to some activists, such as David Popenoe, a sociology professor at Rutgers and president of the National Center for Marriage and the Family, the basic problem is that men are not "biologically as attuned" to being committed fathers as women are to being committed mothers.
"Left culturally unregulated, men's sexual behavior can be promiscuous, their paternity casual, their commitment to families weak," he has written.
Most of the rest of the animal world is also promiscuous by nature. But there are many exceptions besides the prairie vole, such as California mice and gerbils. Among primates, marmosets and tamarins also live in monogamous pairs. They help with the birth of infants, they carry the infants during the day and chew up food for them.
Interestingly, scientists, including those at Amherst, have found that at least with the prairie voles, there is a hormonal basis for good fathering.
Typically after mating, the prairie vole begins to defend his mate, cuddle with her and groom her fur. In experiments where the hormone vasopressin was blocked, the males neither bonded with their mates nor cared tenderly for their pups. But in a notably promiscuous vole species, the meadow vole, the blockers had no effect.
"Prairie voles have brains that have developed to make it more likely that this behavior is displayed," said Amherst professor Geert de Vries.
Over time, their DNA changed because there was an evolutionary advantage.
"The viability of pups increases when the dads are around. They keep them warm, they clean them. Even if they don't nurse them, they make it easier for the female to go after her food and optimize her milk production," he said.
No one is suggesting vasopressin pills to turn casual inseminators into Sensitive New Age Fathers. For one thing, de Vries said, "I'd be surprised to see changes in our vasopressin as you see in prairie voles." Besides, the side effects are unknown. And, too, as Novak observed, what man would willingly take one?
But still, scientists are closer to knowing how transmitter systems in the brain act to change or influence parenting behavior.
Meanwhile, Novak said another study has shown more nurturing behavior in meadow voles that were brought up by prairie vole parents. "You have to have an attitude readjustment here," she said. "It's not a matter of trying to cajole or blame" men to be better fathers, she said. "They have to do it themselves willingly."
* Lynn Smith's column appears on Sundays.