Introduction

In late 1997, a series of exchanges occurred on the internet bulletin board established by Linda Fedigan a year earlier to facilitate communication among the select circle of individuals studying capuchin monkeys (genus Cebus, in the family Cebidae of the New World monkeys). Someone posted a description of a strikingly odd behavior she had noticed in her main study group of about two dozen white-faced capuchin monkeys (C. capucinus). The behavior, a pattern of two individuals interacting in an apparently affiliative manner, had not been described in the literature for any other animal species. Several members of the group performed this behavior with each other routinely over a period of seven years, and it appeared a perfectly familiar aspect of their social behavior that field season, as if they always did this odd thing (see Ch. 14, for more details about the mystery behavior). Nevertheless, they had not done this during the first year of the study, nor had she observed the behavior in the neighboring group. The researcher was understandably curious whether anyone else had ever seen anything like it, or had any ideas on how it might have originated or its function. A flurry of messages ensued over the next few weeks, with several researchers confirming the first person's suspicion that this behavior was not a universal behavior in white-faced capuchins, and not known at all in other species of capuchins.