Species: Allouatta seniculus.
PHYSICAL DESCRIPTION: Male Ht. 2 ft., Wt. 16 lbs. Female Ht. 1.7 ft., Wt. 11 lbs. Coat: Orange-brown. Prehensile tail. Longevity: about 15 years in wild (?).
GEOGRAPHIC LOCATION: Columbia, Venezuela, Guianas, Bolivia, and NW Brazil.
ECOLOGY: High canopy arboreal frugivores. Home range: 10-60 acres. Day range: .5 km. Avian predators, snakes, and cats.
DIET: Mature and young leaves (50%), ripe and unripe fruits (45%)
SOCIAL ORGANIZATION: Large multi-male groups with from 10-80 individuals. Male and some female transfer. Uni-male, age-graded, and multi-male polygynous groups. Male dominance hierarchy in multi-male groups. Aggressive intergroup relations, howling, territoriality. Infanticide after male takeovers.
REPRODUCTION: No birth seasonality. Males sexually mature at 5 yrs., females at 4 yrs. Gestation length: 6 months. No visual estrus swelling. Litter size: 1. Interbirth interval: 2-3 yrs. Infant birth wt. 2 lbs.
PARENTAL CARE: Infants carried by females for 6 mo. allomothering by other females. Weaning at 1 yr.. No active male care, but possible protection.
TOPIC OF SPECIAL INTEREST: Vocalizations. Variability of group composition.
Crockett, C.M. 1985. Population studies of red howler monkeys. National Geographic Research 1:264-273