Monkeys in enduring relationships show a surprising correspondence in their levels of oxytocin, a key behavioral hormone, according to research published online June 28 in the journal Hormones and Behavior.
While measuring oxytocin in the urine of 14 pairs of cotton-top tamarins,Charles Snowdon, a University of Wisconsin-Madison professor of psychology, observed a wide range of hormone levels.
But he also saw a striking correspondence among the couples: When one mate had a high level of oxytocin, so did the other, and vice versa. Furthermore, partners with a high level of oxytocin performed correspondingly more cuddling, grooming and sex, while those with low levels of oxytocin spent less time on these relationship-building activities.
