Rick Jervis

USA TODAY

ORLANDO – It’s not quite Planet of the Apes.

But bands of feral rhesus macaque monkeys are roaming Central Florida, scaring families with their aggressive behavior, making homes in suburban backyards and puzzling wildlife officials who struggle to curb their growing numbers.

The latest monkey-to-people encounter occurred last month, when several of the monkeys charged a family vacationing in Silver Springs State Park, about 75 miles northwest of Orlando. A cell phone video of the monkey business, captured by a family member, is spreading through various social media sites.

Last week, officials at the Florida Fish and Wildlife Conservation Commission formed a working group to gather more information on the monkeys and brainstorm what to do with the roaming primates, which came to Florida more than 80 years ago as a tourist attraction.

“We want to know how many there are, how many troops, where they’re gravitating to and what can we do about them,” commission spokesman Greg Workman said. “These are the things that are unanswered that we really need to know.”

Native throughout Asia, the six rhesus macaque monkeys were brought into Silver Springs State Park – then privately-owned – in the mid-1930s as a way to draw tourists. An additional six monkeys were introduced around 1948, according to a recent study by the University of Florida.

The rhesus macaques were put on an island in the Silver River, but quickly swam to the surrounding forests, spreading through wooded corridors into nearby neighborhoods, said UF wildlife biologist Steve Johnson, one of the authors of the study. Now scientists estimate there are 200 primates in Silver Springs State Park alone. Another 72 have been sighted around Central Florida and the Florida Panhandle, from rural Franklin County in the Panhandle to posh Sarasota on the Gulf Coast.

The native range of the rhesus macaque is the largest of any non-human primate, according to the UF study, spreading from Afghanistan to the Pacific coast of China, a distance of more than 3,000 miles. So males who stray from their troops can travel for miles looking for another group, Johnson said.

“They’re a very adaptable species,” he said. “It’s no surprise they’ve succeeded in spreading as much as they have.”

The monkeys, who live in groups, or troops, usually avoid people, but they can become aggressive if they feel their turf is threatened.

Susie Ramsey, of Estero, Fla., learned that the hard way recently, while on a family vacation with her two sons, Thatcher, 11, and Hunter, 8, and her two parents at Silver Springs State Park. The family encountered a troop of monkeys near a wooded pavilion. At first the monkeys scattered, then four male monkeys charged the family, grunting and hissing, Ramsey said.

The monkeys blocked the trail’s entry and closed in on some family members, she said. They charged and hissed for about 50 yards before turning back.

Ramsey said there were no signs warning of the monkeys’ behavior, though park officials have said fliers related specifically to the monkeys are placed in kiosks throughout the park. Some areas of the park have been closed due to increased monkey activity.

“It was like, ‘Oh cool look at the monkeys,’ then all of a sudden, ‘Oh my God, our lives are in danger!’” Ramsey said. “We did not do anything to provoke this.”

An Ocala man earlier this month photographed more than 50 of the monkeys swarming over his property and feeding off a deer feeder.

And other rhesus macaque monkeys have been spotted recently in Fruitland Park, Fla., around 30 miles south of Silver Springs, and Apopka, Fla., around 70 miles south, lounging on neighbors’ roofs and picking oranges from trees. The monkeys mostly keep to themselves, neighbors said.

"Let 'em alone, they're not doing nothing to you; they're not hurting you," resident Rose Ackley, 22, told WKMG-TV in Orlando.

Researchers trying to gather more information on the monkeys, including population estimates, mating habits and impact to the environment, have faced resistance from animal rights’ activists who protest some of the research techniques.

A few years ago, Johnson and his colleagues were forced to cease a study tracking the rhesus macaque monkeys after animal rights’ groups protested tracking collars used on the animals, he said. That puts wildlife officials in a quandary: They don't have enough information to track the monkeys' movements, manage their populations and halt their aggressive encounters with humans. Some of the monkeys also carry the Herpes B virus, which is lethal in humans.

Ultimately, it'll be up to state park officials to determine what to do with the monkeys, he said. For now, wildlife officials say they're not even considering population control, such as trapping the monkeys.

“I don’t envy them having to make this decision,” Johnson said. “It’s something they’re dealing with and ultimately going to decide what to do.”