Adapting to Florida’s riverine woodlands: the population status and feeding ecology of the Silver River rhesus macaques and their interface with humans
The study of primates living in novel environments represents an interesting context in which to examine patterns of behavioral and ecological flexibility. Our research focused on an understudied, anthropogenically introduced primate population living in Florida, USA: the Silver River rhesus macaques (Macaca mulatta). To better understand how this population has adapted to life in Florida’s riparian woodlands, we collected data on the diet and size of the rhesus macaque population and its encounters with boaters along the Silver River from January to May 2013. Using scan sampling and all-occurrences sampling, we collected 166 h of diet data and 105 h of human-macaque encounter data, respectively. We confirmed previous reports that four social groups comprise the Silver River macaque population, totaling 118 individuals. The Silver River macaques predominantly consumed leaves and other vegetative plant parts (87.5 %), with ash trees serving as a staple food (66.5 % of feeding records). Although human-macaque encounters were frequent (80 % of 611 boats observed), only a small proportion of boats (11.5 %) provisioned the macaques. Motorized boats (e.g., pontoon and motor boats) were more likely to provision, while kayaks and canoes were more likely to move in close proximity of the macaques situated at the river’s edge. Our results indicate that the Silver River macaques have adjusted to life in the New World by adopting a temperate-dwelling feeding strategy and by incorporating locally available foods (e.g., sedges) into their diet. They have also learned that the river’s edge provides opportunities to receive provisions from boaters. However, because the rate of provisioning is low, these foods likely play a filler fallback role. Given that provisioning and direct contact between macaques and boaters are infrequent but proximity to the macaques is a concern, our findings have important implications for the management of the human-macaque interface along the Silver River and beyond.