Invasive macaque populations in Gibraltar, Mauritius, and Florida create management controversies between the welfare of individual primates and their ecological impacts on native species.
Macaques are highly intelligent, social primates whose culling for population management causes complex welfare harms — fear during capture, social disruption from removal of group members, and acute suffering during killing. Unlike fish or invertebrates where welfare is debated, primate welfare harms from lethal management are unambiguous. Fertility control through immunocontraception is feasible for macaque populations but requires significant ongoing investment. The welfare case for non-lethal management of invasive primates is stronger than for most other invasive species given their cognitive complexity.