U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version



Published in Crop Protection 29 (2010) 401–405.


Beginning in the 1930s and continuing through the 1970s, rhesus macaques and patas monkeys were introduced to presumed secure locations, primarily coastal islets, in Puerto Rico. Escapes into the wild began almost immediately after introduction. Today the combined range of the two species covers approximately 600 km2 of southwestern Puerto Rico, where serious conflicts with agricultural interests have resulted. The Puerto Rico Department of Agriculture surveyed about 90% of commercial farmers in the range of the monkeys to begin quantifying damage by monkeys and the associated economic losses during the years 2002–2006. During that time, total economic losses by commercial farmers to monkeys increased from $1.13 million USD to over $1.46 million per year. Of these amounts, the economic losses due to farmers avoiding monkey damage by switching from fruit and vegetable crops to less rewarding land use (primarily hay or pastureland) increased from $490,000 to $1.33 million per year. The losses reported from the survey represent only a portion of economic losses to the invasive monkeys. Subsistence and other smaller farms and agriculture were not included in the survey. We also discuss many other economic issues surrounding the impacts of the invasive monkeys, but for which sufficient data are not available for economic analyses. These include concerns such as destruction of native (especially endangered) wildlife, threat of disease spread, and property damage, all of which would also have to be considered to fully evaluate invasive monkey economic impacts in Puerto Rico.