Paternal In-stinks

Innumerable studies have explored the olfactory bonding between new moms and their babies, but what about new dads? Are they geared to think with their olfactory organs, with respect to their own offspring?

Absolutely, according to a new study by the Wisconsin National Primate Research Center at University of Wisconsin-Madison, at least in the case of lower primates. A whiff of his own little tyke will cause a marmoset father’s testosterone levels to drop off, lowering both his tendency toward aggressive behavior and his interest in philandering.

“Essentially, this encourages the father to be there for the child,” says WNPRC staff scientist Dr. Toni Ziegler, whose team conducted the study by isolating experienced male marmoset fathers from their families, then exposing them to either the scent of their own infants or a control scent. Males with no experience as parents were exposed to the same odors. Blood tests taken within 20 minutes of exposure revealed a significant decline in testosterone in every single one of the experienced dads presented with the odor of their own offspring, while the bachelor marmosets were completely indifferent. “We were a little surprised to see testosterone alter like that,” admits Ziegler. “This shows the male is responsive to chemical cues from his infants.”

Testosterone is the most abundant male hormone in primates, including humans. And marmosets, small South American monkeys, were a prime-primate choice for the experiment because they, like humans, tend to place nearly as much parental responsibility on the father as the mother.