For over 70 years, a small population of African green monkeys has been thriving in a mangrove forest near Fort Lauderdale-Hollywood International Airport in Florida. A team of researchers recently conducted a genetic analysis to determine the monkeys’ origin story, and it turns out that they’re longtime Florida residents and likely descendants of a 1948 zoo escape.
Though the monkeys are familiar to local humans, no one knew their exact biological identity or geographical origins until the recent research efforts. The primates are green monkeys, the researchers report in the journal Primates. Native to West Africa and called green for the tint of their tan fur, the monkeys were brought to a research facility in Florida sometime in the 1940s. The lab, purchased in 1939 by a cousin of Theodore Roosevelt, also functioned as a zoo and tourist attraction and hosted chimpanzees and mandrills along with the green monkeys. Primates from the facility were used as test subjects for the polio vaccine, and some were received by Jonas Salk. They were also used for studying tuberculosis and other infectious diseases. In 1948, 50 primates escaped from their enclosures, and only about two-thirds were recovered, according to the new paper, which among other things considered historical interviews with employees of the research facility. The runaway monkeys moved deeper into the mangroves and clearly got along just fine.
To determine the monkeys’ exact species, the team photographed all 36 individuals in the wild population and traced three genetic markers in the animals, picked up from five fecal samples and one tissue sample. That confirmed the animals were part of a genus of Old World monkeys known as Chlorocebus, a group that also includes vervets, grivets, and the malbrouck. But the green monkey has specific characteristics that separate it from the bunch.
“Our monkeys in Dania Beach have a golden-tipped tail and greenish-brown hair, lack a pronounced brow band around the face, and males have a pale blue scrotum,” said Deborah “Missy” Williams, a biologist at Florida Atlantic University and lead author of the study, in a university press release. “These phenotypic traits are characteristic of Chlorocebus sabaeus.”
The specification was necessary. There are three primate species in Florida—squirrel monkeys, rhesus macaques (many of which are infected with super herpes), and these green monkeys—all of them introduced from elsewhere in the world. Williams currently leads the Dania Beach Vervet Project, which is devoted to conserving and studying the local monkey population.
While it’s impossible to speak for a monkey, it’s clear that they’re making the best of their situation in the mangroves. No longer stuck in cages like their recent ancestors, they now munch on peanuts in parking lots and have a generally decent go of it in the trees.