Without the use of words, what’s the best way to connect with someone you know? How would you say “you’re my friend” or “I’m sorry” or “I love you”? How could you communicate a feeling of complete, unselfish affection if you felt the urge? Human beings have invented endless means of sharing emotions when words aren’t an option, or fail to say enough. Gestures of emotion can take many forms. For most animals, nonverbal communication is and always has been their sole option. For the snow monkeys of Hell Valley, one specific act fits a full range of situations in which one may wish to express an affinity for another.
The act of self-grooming is essentially a cleansing routine—a return to normalcy. Ridding the body’s exterior of foreign debris—like a cat giving itself a bath—seems to primarily serve as a hygienic practice, ensuring better health for the well-groomed. However, when an individual grooms another, several added benefits emerge. In addition to restored hygiene, partnered grooming builds and exercises social bonds. Grooming another individual can be a habitual part of a relationship, but could also function as a specific gesture, such as an offer of new friendship, an act of reconciliation after an altercation, or a sign of general caretaking and affection, all of which are supported by the positive chemical reactions caused by physical touch.
Professor Lauren Brent of Duke University has spent six years studying the friendships of a single troupe of monkeys. Her research shows that those who engage in social behavior have lower levels of stress hormones. Partnered grooming is a common social interaction and is therefore an important part of a healthy relationship. Physical touch from another monkey, in a friendly nature, will cause the hormone oxytocin to be released, sending a pleasing sensation through the body. As involvement in this activity increases, stress levels decrease, allowing for longer survival, and a higher rate of producing healthier infants for females.
Because grooming is a social affair, offering one’s services will result in receiving a grooming more often. Either role, giving or receiving punches an individual’s ticket into a more stress-free, cleaner, expressive lifestyle, giving rise to improved health and relationships.
Funder:Major support for NATURE is provided by the Arnhold Family, in Memory of Clarisse Arnhold, the Lillian Goldman Charitable Trust, and the Filomen M. D’Agostino Foundation. Support is also provided by the Corporation for Public Broadcasting, and PBS.