LAUSR

Coping styles describe behavioral differences during stressful or challenging situations. Coping styles are stable over time but little is known about early life manifestation and development of these behavioral differences. We aimed to investigate if differences in the way marmosets produce vocalizations at an early age are related to their coping style in the future. We studied 14 common marmosets (Callithrix jacchus) from three social groups housed at the marmoset colony at Universidad Autónoma de Madrid. We recorded the vocalizations of each marmoset in isolation at 15–17 days of age, analyzing latency to vocalize and calling rate of phee and tsik calls. To measure coping style, we introduced a novel stimulus to the group cages when infants were 3 months old and recorded exploration, headcocking, and approaches to the stimulus. The results showed negative relationships between the latency of phee call (a long-range contact call) at 15–17 days and frequency of exploration and approach to the novel stimulus at 3 months, although both correlations fall above the cut-off points for the false discovery rate. Marmosets that gave long-range calls sooner at 15–17 days of age also showed more exploratory behaviors at 3 months. The results also showed group differences in exploration at 3 months, and twins were more similar to each other than to other infants in the sample. There were no group differences in early vocalizations and no sex differences in any variable. These findings suggest that coping style is stable from as early as 15–17 days after birth and suggest that the group can influence exploration in marmosets.