Monkey Forest Tales: What we have learned about red howler monkeys over the past 15 years?


This is the fourth post of a series in which the findings of this project are presented. In this post, the findings for the red howler monkeys are described. Red howler monkeys are the biggest primate species inhabiting the study area. They are also the most common species present in the area.

Where do you find them depends on the number of forest patches the landscape has, this means that it is more possible you find groups of red howler monkeys in landscapes where there are a lot of forest patches of any size. How many red howler monkeys you find in a landscape depends on how tall the forest is and the form of the forest patch (Carretero-Pinzón et al 2017).

Red howler monkeys use living fences as part of their home ranges, suing them to get access to other forest fragments and to find fruit and leave sources. Most of the living fences used by red howler monkeys have trees of more than 10 m height (Carretero-Pinzon et al 2010).

Red howler monkeys can survive in small forest fragments (< 5 ha) using them as home range as well as stepping-stones during male’s dispersal (Carretero-Pinzón unpublished data). We have seen males dispersing using pastures, wire and living fences, as well as passing secondary and tertiary roads (Carretero-Pinzón unpublished data, local people reports). Sometimes they also use electricity poles and cords to move, which causes them electrocutions (Local people reports). Recorded dispersal distance in the area is up to 4 km (Local people reports).

They can live in fragments of gallery forest, lowland forest and swamp forest (forest patches composed mainly of Mauritia flexuosa with soils of a high-water table; Carretero-Pinzon & Defler 2018). Red howler monkeys can live in rural and urban landscapes in the Colombian Llanos.

Red howler groups spent more time moving in search of food in smaller fragments than groups living in bigger fragments (Escudero 2005). Red howler monkey tends to consume more fruits, young and mature leave in larger forest fragments compared with smaller fragments. In the study area, we had found that they consumed plant species that are different from the families they consumed in continuous areas (Escudero 2005). They have been observed using herbaceous plants in the pastures near to the forest fragment edges, up to 200 m from the edge, eating on the ground in open pastures (Carretero-Pinzón unpublished data).

Red howler monkeys live in groups from 1 to 9 individuals in the study area, usually a couple of males and a few females and their offspring, similar to groups in continuous areas (Carretero-Pinzón unpublished data). Solitary males had been observed in the study area in fragments of different sizes (Carretero-Pinzón unpublished data).

Red howler monkeys had been observed covered by human bot fly in the fragmented and continuous area. In the study area, this external parasite seems to be more common in red howler groups living near to palm oil plantations (Carretero-Pinzón unpublished data).

Red howler monkeys are good seed dispersers and in the study area, they have been found to be highly selective. Seeds dispersed by this species is also different depending on the season in which the study is made. They are good disperser of fig species (Ficus spp.) in fragmented areas (Gaitan-Naranjo 2009). A comparison of the two main areas of this project found that in the area around the Unamas Natural Reserve red howler disperse more species than in the Santa Rosa area, this is related to the plant diversity found in those areas (Gaitan-Gomez 2017).



Carretero-Pinzon X., Defler TR. 2018. Primates and flooded forest in the Colombian Llanos. En: Barnett AA, Matsuda I, Nowak K (eds) Primates in flooded habitats: ecology and conservation, Cambridge University Press, Cambridge, UK.

Carretero-Pinzón, X., T.R. Defler, C.A. McAlpine & J.R. Rhodes. 2017. The influence of landscape relative to site and patch variables on primates distrubition in Colombian Llanos. Landscape Ecology 32: 883-896.

Carretero-Pinzón, X., T.R. Defler & M. Ruíz-García. 2010. Uso de cercas vivas como corredores biológicos por primates en los Llanos Orientales. In: Primatología en Colombia: avances al principio del milenio. Pereira-Bengoa, V., Stevenson P.R., Bueno M.L. & F. Nassar-Montoya. Fundación Universitaria San Martín. Bogotá, Colombia.

Escudero, S.P. 2005. Patrón de actividad, recorridos diarios y dieta de Alouatta seniculus en fragmentos de bosque de galería San Martín Meta. Pontificia Universidad Javeriana. Bogotá, Colombia.

Gaitán-Gómez, D. 2017. Comparación del tamaño y la capacidad de germinación de semillas dispersadas por Alouatta seniculus en paisajes con diferentes grados de fragmentación, durante la época de lluvias en San Martín, Meta. Pontificia Universidad Javeriana. Bogotá, Colombia.

Gaitán-Naranjo 2009. Dispersión de semillas por parte de Alouatta seniculus en fragmentos de bosque (San Martín, Meta). Pontificia Universidad Javeriana. Bogotá, Colombia.

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