Costs and benefits of post-weaning associations in mountain goats.

To better understand the potential costs and benefits of prolonged parental care in gregarious species, we studied post-weaning associations in a marked population of mountain goats (<italic>Oreamnos americanus</italic>) monitored for 22 years. We calculated the occurrence and frequency of associations involving 1- and 2-year-old juveniles. We investigated (1) the influence of maternal characteristics and population size on the formation of post-weaning associations, (2) the short-term costs of associations on maternal reproductive success, and (3) the short-term benefits of associations on life-history traits of juveniles. We found that barren mothers associated more frequently with 1-year-olds than summer yeld and lactating mothers. Associations with 2-year-olds tended to increase the probability that a mother would be barren the following year. Post-weaning associations did not influence the body mass of newborn kids nor the body mass and survival of juveniles. We discuss how benefits for associated juveniles may appear later in life. [ABSTRACT FROM AUTHOR]