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A birth during the day by a capped langur (Trachypithecus pileatus Blyth, 1843) was recorded at Pakhui Wildlife Sanctuary, Arunachal Pradesh, India. The birth took 43 min. Allomothering was observed 3 h after the birth. An average of 9% of daily active time was shared by four allomothers (three adults, one subadult) during the first 15 days of the infant's life. Total time allomothering was proportional to the age of the allomothers (241 min for oldest; 214 min for youngest).

We studied reproductive behavior of free-ranging capped langurs (Trachypithecus pileatus) in the Pakhui Wildlife Sanctuary, Arunachal Pradesh, India. Four species of primates -Trachypithecus pileatus, Macaca mulatta, M. assamensis, and Nycticebus bengalensis-live there. We studied the mating seasons, mating frequency, copulatory attempts, time spent in copulation, and interval between 2 successive copulations, gestation length, and interbirth interval of 4 groups of capped langurs during 2001-2003. We observed 2 mating seasons in a year. The first was larger, comprising 5 months (September-January), and the second was short, April and May. Mating was intensive in the morning session (0600-1000 h); 57% of total mating events occurred then. The average gestation period was 200 d. November was the most favorable month for breeding. In a year, 107 mating events occurred involving 5 adult females. Average time per mounting attempt is 12 s. Duration of mounting was the maximum in November. Interbirth interval was 23 months and 10 d. The birth season was 129 days, December-April; 53% of births occurred in February and March. Average birth rate is 0.386 birth/female/yr.

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We observed a group of capped langurs for 12 mo in the Pakhui Wildlife Sanctuary, Arunachal Pradesh, India. We recorded the time of feeding on different food plant species, food categories, and the feeding heights of monkeys in trees. Capped langurs spent 68% of their feeding time on leaves, 16% on flowers, and 16% on fruits. Feeding on leaves was consistently high (p<0.01) during the year, with the highest feeding in May (85%) and the lowest in January (47%). The seasonal difference in feeding on leaves is significant (p<0.05): it was higher in summer and during monsoon. The feeding time on flowers was maximal (35%) in March and that on fruits and seeds was minimal (38%) in January. Langurs ate 52 plant species throughout the year. The largest number of plants (6) were species of Moraceae, and langurs spent more feeding time (20%) on them alone. The number of plants eaten per month varied significantly (p<0.05). Langurs ate Gmelina arborea, Albizzia lucida, Ficus glomereta, and Makania micrantha throughout the year. They spent 44% of their feeding time in terminal canopies and their average feeding height was 30-35 m. This is the first study to examine the feeding ecology of capped langurs and provides baseline data for the species.