Vervet monkeys are a group of black-faced monkeys with pale grey/green fur, though there is some variation across the subspecies included within the group. Native to countries across Africa, they’re not what you might expect to see when in Florida but a population of vervet monkeys has taken up residence in the US state regardless. Despite the peculiar location of the population, there’s been little in the way of scientific investigation as to how and why they came to be there.

Now, a new study published in the journal Primates has established that these monkeys originated from a farm from which some animals escaped back in 1948. They’ve since made a home for themselves in the mangrove forest near the Fort Lauderdale-Hollywood International Airport, South Florida. Despite being so far from their native homes, the vervet monkeys have survived quite happily for over seven decades.

The monkeys have long been a hit with the wider public, but - bar an early 1990s study - nobody has tried all that hard to work out the story of the unlikely primate settlement. A team of scientists from Florida Atlantic University decided to give the puzzle a go, building on the suggestion of the one existing study which hypothesized a failed roadside zoo may have been their origin story.

The team’s multifaceted approach sifted through historical archives and conducted interviews to establish the likely source: the Dania Chimpanzee Farm. When it was operational, that facility dealt in primate imports to act as test subjects for vaccine research including treatments for polio, among other diseases. It also acted as a zoo and was home to many monkeys imported from Africa.

Their archive surfing revealed that the original Diana Beach monkeys were most likely first captured in Sierra Leone. The theory was able to be confirmed by analyzing samples from the existing population for signs of three genetic markers associated with the Diana Chimpanzee Farm group. The analysis confirmed that the Dania Beach monkeys are indeed the same species (Chlorocebus sabaeus) and have West African origins, fitting the Sierra Leone vervets’ genetic profile.

Photographs of the Diana Beach monkeys alive today also support this theory, sharing specific physical traits that concur with animals native to West African countries. These include fur color, tail tip color and even the color of the scrotums sported by the males. A qualitative comparison of these phenotypic traits was found to be characteristic of Chlorocebus sabaeus.

"Data from our study lays the groundwork for future studies to address new questions about the status of the population and how the monkeys have adapted to the urban and industrial environment of South Florida," said Dr Kate Detwiler, senior author and an associate professor in the Department of Anthropology in FAU's Dorothy F. Schmidt College of Arts and Letters. "The correct taxonomic identification and history of the introduced Dania Beach monkeys is important for community outreach and wildlife management, given the remarkable ability for Chlorocebus to thrive in most environments."