Behavioral Ecology of the Patas Monkey (Erythrocebus patas) and Conservation Challenges in Alatish National Park, Northwest Ethiopia

No Thumbnail Available



Journal Title

Journal ISSN

Volume Title


Addis Ababa University


The results of both qualitative and quantitative investigations on the behavioral ecology of the patas monkey (Erythrocebus patas) and conservation challenges at Alatish National Park are presented in this dissertation. The study aimed at the behavioral responses of patas monkeys to their seasonal lowland habitats and evaluating the taxonomic status of the patas monkeys found in Ethiopia as well as the conservation threats the park faces. The field study was carried out from November 2011 to April 2013 in two wet seasons and two dry seasons. Behavioral data were collected through 15 minutes scanning samples of 10 hours and 30 minutes field observations a day, particularly on feeding, activity time budget and ranging patterns. Morphological features of all age groups and sexes were also noted during both wet and dry seasons. Seasonality in feeding behavior was tested through Schoener’s dietary niche overlap index and Levins' dietary niche breadth index. Effects of seasonal changes on activity time budgets were statistically tested by MANOVA; ecological factors that determine activity time budget were statistically analyzed by MANCOVA. Daily range length and home range size were estimated using OpenJump toolbox (MOVEAN), and statistically tested by t-test and Wilcoxon test. Kernel density (95%), MCP (95%), and grid cell home range estimation methods were also used to estimate home range sizes. Conservation threats were studied through field observations and Landsat Satellite Imagery Analysis. Erythrocebus patas found in Ethiopia have some distinctive morphological features compared with E. p. pyrrhonotus. The adult males face is fully black without a white spot on their nose. Adult females also have a white frontal band. Food items such as gum (39%), fruits and flower buds (32.7%), Acacia pod (0.6%), crop seed (8.1%), herb stem pith (3.5%), corm/tuber (14.8%), and insect (1.3%) contributed to their annual diet composition. Patas show dietary switching in response to seasonal changes. The diet similarity between wet season and dry seasons was only 15.5%. Dietary niche breadth of patas was also narrow during dry seasonal. Moreover, this study found that within their daylight activity time budget, Patas monkeys spent 16.71% feeding, 22.75% moving, 11.26% social activity, 32.03% resting, 14.93 % vigilance and 2.33% other activity. The results of multivariate analysis reveal that season has a statistically significant effect on activity time budget, Wilks’ λ = 0.21, F = 17.14, df = (6, 27), p < 0.001, η2 = 0.79. Analyses on the effect of ecological factors in activity time budget also show that food availability or dietary niche breadth, temperature, ectoparasite infestation and predation risks significantly determine seasonal changes in activity time budgets. Patas monkeys respond to seasonal environmental changes in their ranging behavior. Day journey lengths varied between wet and dry seasons (t= - 8.4, df = 28, p< 0.001) with long (1,512.8m (±466.18) daily travel length during the dry season. Home range size of the wet season was 36.19651 hectares (±15.5196), whereas in the dry season it was 105.29439 hectares (±104.7916). Wildlife dwelling in the Park have been affected by habitat degradation caused by human induced fire and dry season water and food resource scarcity. The land cover change analysis found that woodland cover of the Park is highly altered. Finally, based on morphological features and feeding behavior, the study suggests that patas monkey in Northwest Ethiopia is distinct enough from E. P. pyrrhonotus and warrant designation as a new and distinct subspecies. Key words: Erythrocebus patas, feeding, activity time, ranging behavior, Alatish National Park, conservation challenge



Erythrocebus Patas, Feeding, Activity Time, Ranging Behavior, Alatish National Park, Conservation Challenge