The behaviour of the red howler monkey (Alouatta seniculus) in the Llanos of Venezuela was studied from May 1975 to May 1976. The average size of the social groups was 6.3±2.1 individuals. The groups were heterosexual, comprising individuals of all ages, with an average of 40% adult females, 26% adult males, 16% juveniles and 18% infants. The daily rhythm of activity for the performance of locomotion, feeding, snoozing and sleeping was ascertained for dry and rainy seasons. The density of the population in the whole area of study was 0.25 individuals per hectare of woodland, although a density of as high as 0.54 individuals per hectare was reached in some places. The use of space was established by means of locations, howls, fecal piles and scent-marking. Howlers discriminated very much in their performance of various activities in the vertical strata of trees, their use being apparently controlled mainly by the howlers' quadrupedal locomotion and by the necessity for protection against predators.

Peer reviewed