ABSTRACT

It is a red letter day for our capuchin project in Costa Rica. After locating one of our study groups in its usual home range, a student and I notice that a young female named Kathy Lee (KL) has what appears to be a small grey lump on the back of her neck. Looking through binoculars, we can make out the body of a tiny infant slung across KL’s upper back with its eyes closed and head hanging down in the crook of her neck, while KL forages with the rest of her group and leaps nonchalantly from tree to tree. We are excited because this is one of the first times that we have tracked a female from the day of her own birth through the birth of her first offspring. KL has many relatives in the group. She is the alpha female of the group and the eldest daughter of the prior alpha female that died a year earlier. As the day progresses, several group members approach KL to sniff and touch the new arrival. KL’s sister seems particularly interested and stays close to the new mother-infant pair, grooming them when they rest. We feel some concern for this new infant because there has been instability among the adult males of the group and we know that male fighting can lead to the death of small infants. When the group decides to rest in the park’s campground, we radio to other members of our team who are elsewhere in the forest and back at our research house to come see the new infant.