Possible Herpes-Infected Monkeys Invade Florida Coast

By author of The Realblog with Stephanie Mallory

The invasive rhesus macaques pose a risk to native wildlife and people too

The headline for this story sounds like the title of a low-budget horror movie, but believe it: Monkeys — that could be infected with herpes — are spreading across parts of Florida.

According to First Coast News, in recent months there have been numbers of sightings of invasive rhesus macaque monkeys in Jacksonville, St. Johns, St. Augustine, Palatka, Welaka and Elkton. 

“The potential ramifications are really dire,” University of Florida wildlife ecologist Dr. Steve Johnson told First Coat News. “A big male like the one in that video in Jacksonville — that’s an extremely strong, potentially dangerous animal.”

Florida Fish and Wildlife Conservation Commission (FWC) officials say the monkeys likely originated from the feral monkey population in Central Florida. A tour boat operator named Colonel Toey released six rhesus macaques on a manmade island in Silver Springs State Park in the late 1930s as a tourist attraction. He released an additional six a decade later.

“Guess what?” laughs Johnson. “They can swim. They left the island.”

The monkeys have lived in the state park since then and have extended well beyond the park boundaries, as far as Tampa and Apopka, but this is the first time the monkeys have been reported on the First Coast.

Julington Creek resident Carrie Bennett said she's worried about the primates. “That is definitely a concern because I walk the dogs at like 5:30 in the morning and it's pitch blackout,” she said. “If they bit me, if they came after and bit you, you don’t know what they have, what they’re carrying.”

Officials do know that the monkeys carry — and shed — the Herpes B virus, which can be fatal to humans. Johnson calls it a “low-risk, high-consequence” possibility. He says they also have “strong arms, a very strong bite [and] large canine teeth.” 

Two years ago, in response to a report about the increasing macaque population and the presence of Herpes B, state wildlife managers released a statement in support of population control.

“Without management action, the presence and continued expansion of non-native rhesus macaques in Florida can result in serious human health and safety risks, including human injury and transmission of disease,” FWC Assistant Executive Director Thomas Eason said. “Additionally, macaques can negatively impact Florida native wildlife and pose potential risks to agriculture and recreation. Therefore, the FWC supports active management to remove these threats.”  

But FWC has not defined “active management," and no population control efforts have been made since 2012. (The agency did make it illegal to feed monkeys in 2017.)

The agency said it "will continue to monitor reports of monkeys in the Jacksonville area ... and will respond to individual monkeys acting aggressively and posing an immediate safety threat." 

Johnson says the history of monkey population control may explain regulators' reservations. From the original 12 macaques introduced in the ’30s and '40s, their numbers and their range grew. In 1968, the population in Silver Springs State Park was estimated to be 78. By the 1980s, the population was almost 400, with many others inhabiting the forests along the Ocklawaha River.

Beginning in 1984, the then-Florida Game and Freshwater Fish Commission allowed licensed trappers to cull the monkey population. From 1984 to 2012, they trapped and removed approximately 1,130 rhesus macaques. Hundreds were sold to biomedical research facilities, some were taken to zoos and some were killed. The program was deeply unpopular with the public.

Some monkeys were even sterilized and returned in an effort to control the population, but Johnson said his research shows that effort was ineffective. He explained that even if researchers could trap and sterilize 80 percent of female adults every five years, the population would only stabilize, but would not reduce.

Without a plan in place to slow their growth, Johnson said their numbers will increase. He admits the monkey problem is a difficult one to solve. 

“Big, scary 15-foot Burmese pythons or nasty feral pigs are one thing, but primates that look like people, that are furry, it’s a much more difficult challenge,” he said. “It would take political will, and it would also take a lot of money. I don’t envy them one bit.”

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