Ecological and behavioural flexibility of mantled howlers (Aloautta palliata) in response to anthropogenic habitat disturbance

While howlers are the most ecologically flexible of the atelines, they must still respond to issues arising from anthropogenic modifications, such as fragmentation or dietary changes. A group of Alouatta palliata living in a highly modified landscape (commensal group) at the Curú Wildlife Refuge in Costa Rica was compared to howlers with limited human influence (control group). The commensal group had a more frugivorous
diet than the control group (H = 9.23, p = 0.002) due to crop-foraging of mango fruits. The commensal group maintained a larger home range than the control group, at 39 and 10 ha, respectively. The commensal group also had increased travel (H = 7.37, p = 0.007) and feeding (H = 7.34, p = 0.007) time, as well as reduced proximity to conspecifics (H = 44.77, p = 0.000). There were no significant differences in rates of either aggressive or affiliative social behaviours. The increased home range, shift in diet, increased travel and foraging time and reduced group cohesion demonstrated by these animals represent responses to the varied utility of available landscapes and the more widely
dispersed resources in their range. These data contribute to our understanding of Alouatta, one of the most successful of Neotropical primates in modified landscapes.