Surviving in the urban-rural interface: Feeding and ranging behavior of brown howlers (Alouatta guariba clamitans) in an urban fragment in southern Brazil.

Wild primates that live in urban areas face extreme threats that are less frequent in nonurban fragments, such as the presence of dangerous matrix elements (e.g., roads, power lines, buildings, and a high density of domestic dogs near food patches), that could influence their movements, feeding behavior, and survival. However, the scarcity of studies addressing this issue hinders our understanding of the behavioral adjustments that favor the survival of primates in urban areas. For 12 months, we studied a six-individual group of brown howlers (Alouatta guariba clamitans) in an urban fragment to determine (i) their diet richness and its relationships with food availability, (ii) their daily path length (DPL) and the matrix elements used during movement, and (iii) the main ecological drivers of the DPL. Sampling effort totaled 72 days, 787 hr, and 3,224 instantaneous scans. We found that the diet of brown howlers contained 35 plant species (including seven cultivated crops) belonging to 33 genera and 21 families. The consumption of fruits and young leaves was directly related to their temporal availability. The average DPL (446 m) was smaller than that reported for groups of howlers inhabiting large nonurban fragments. To move between food patches, animals used three main matrix elements: trees, power lines, and roofs. The number of plant species used during the day was the main driver of DPL. Our findings highlighted that the generalist-opportunistic diet of brown howlers and their ability to move across the anthropogenic matrix using artificial elements such as power lines, roofs, and wildlife crossings represent a remarkable part of their behavioral repertory in Lami. However, there are potential costs associated with these strategies, namely, electrocution and predation by domestic dogs. Thus, it is urgent to further investigate how these behaviors could affect the long-term survival of these animals.