The question of whether wild monkeys exist in the United States is complex, requiring a distinction between species that are native and those that have been introduced. The continental U.S. does not contain any non-human primate species indigenous to its ecosystems. However, several established, self-sustaining populations of monkeys that originated from outside the country have successfully taken root in specific, localized environments. These non-native groups and occasional transient escapes account for the monkey sightings.
Native Primate Species in North America
The continental United States is entirely without a population of non-human primates that can be considered native wildlife. While the North American continent extends south to include Mexico and Central America, where species like howler and spider monkeys are indigenous, their natural range stops well short of the U.S. border. The ecological conditions necessary for primates, which generally prefer tropical or subtropical rainforests, are not widely present enough to support them naturally in the U.S.
The last non-human primate to inhabit North America was a small, lemur-like creature called Ekgmowechashala, which went extinct millions of years ago. Following a major climate cooling event around 34 million years ago, the continent became inhospitable to primates. This means that any monkey encountered in the wild within the U.S. today is an introduced species, having arrived either intentionally or accidentally through human activity.
Established Feral Monkey Colonies in the US
Despite the lack of native species, the U.S. is home to several well-established, breeding populations of feral monkeys, primarily in Florida. The most widely known of these is the colony of Rhesus Macaques (Macaca mulatta) living along the Silver River in Silver Springs State Park. This population originated in the 1930s when a commercial riverboat operator released a small group of Asian-native monkeys onto an island to enhance his “Jungle Cruise” tour attraction.
The operator did not account for the macaque’s strong swimming ability, and the monkeys quickly swam to the mainland. They established a wild colony that grew to nearly 400 animals by the mid-1980s. Although population control efforts have been controversial and sporadic, including the removal of over 1,000 individuals between 1984 and 2012, the monkeys continue to thrive. These macaques are highly adaptable, omnivorous, and can carry diseases like Herpes B virus, which poses a public health concern.
Other established colonies exist, most notably a large research-facility-related population of Rhesus Macaques on Morgan Island, South Carolina, which is a protected, uninhabited Sea Island. Florida also has a historically established population of Vervet Monkeys (Chlorocebus sabaeus) near Dania Beach. These monkeys escaped from a research facility in the 1940s. Recent surveys estimate this vervet population to be around 40 individuals split among four groups, demonstrating a stable, long-term presence in the state.
Addressing Occasional Sightings and Escapes
Apart from these established, self-sustaining colonies, most monkey sightings across the country involve transient animals that have recently escaped captivity. These individuals are typically exotic pets, such as Capuchins or Squirrel Monkeys, or animals used in research. Such incidents are localized and temporary, as these species rarely survive long enough to form a breeding population outside of specific warm climates like South Florida.
The legality of owning non-human primates varies significantly by state, which contributes to the potential for escapes. For example, dozens of Rhesus Macaques recently escaped from a research breeding facility in South Carolina, prompting a temporary search and capture effort. These isolated events create headlines and local sightings but do not represent a permanent, wild population in the way the Florida and South Carolina colonies do.