Agonistic and Affiliative Relationships of Adult Female Howlers ( Alouatta palliata ) in Costa Rica Over a 4-Year Period

摘要: We observed 12 adult female mantled howlers (Alouatta palliata), which have been part of Group 2 at Hacienda La Pacifica, Guanacaste Province, Costa Rica, via focal animal sampling during portions July and August 1988 1990–1992 (7–9 females/year, 955.3 hr observation). used agonistic interactions time in proximity (<1 m) as indices social relationships. The rate female–female was 0.38/hr (yearly range: 0.24 to 0.51/hr). Yearly dominance hierarchies, based on outcomes dyadic interactions, varied linearity between 60.7 94.6%. Adult females spent 7.10% their another 1.04–15.64%) 4.95% an male 2.27–7.51%). Using yearly ranks, we tested patterns for differences rank presence dependent offspring. In 3 the 4 years, high-ranking significantly greater proportions with other than did low-ranking females. Time or males not associated rank. Having a infant related proportion males, females, especially top-ranking ones, more infants without infants. These results show that relationships howler groups are dynamic generally support predictions made by von Schaik (1989) regarding scramble-type, competitors. also discuss roles immigrations, infants, patterning