OCALA, Fla. - When you're exploring the great outdoors in Florida, you might expect to see alligators in the water or native egrets flying above. But as one man and his family were boating down the Silver River in Silver Springs State Park, they probably didn't expect to see monkeys leaping from trees into the water right in front of them.
On Dec. 3, Matthew Schwanke was recording video on the Silver River when a troop of more than 20 rhesus macaques began jumping from the tree limbs, loudly splashing into the water below.
"They're all jumping!" one boy could be heard gasping as the monkeys leaped one by one. "Dad, back up!"
Schwanke laughed as he continued recording, all while the macaques kept plunging into the water in rapid succession.
"It's raining monkeys!" he joked.
Schwanke said the incident was the result of a "turf war" between two troops of monkeys.
After watching a confrontation between the two groups break out, he started recording the video, which he said showed the "original troop being run off by the rival troop from the other side of the river."
Schwanke runs the nonprofit Outdoor Valor, which takes veterans on offshore fishing trips as a form of post-traumatic stress therapy.
It's not the first time someone has captured rhesus macaques leaping into the water in Silver Springs State Park.
Back in 2019, Rod Guynn was kayaking on the Silver River when he noticed multiple monkeys in the trees on the side of the riverbed. He recorded video of the monkeys leaping into the water, then swimming across the river to get to the other side.
"Large males were forcing females and babies to dive and cross the river by herding [them] out to the end of limbs, then jumping up and down on the limbs until they jumped/dove in," he wrote on his YouTube page.
State of Florida wants to move herpes-excreting wild monkeys
Hundreds of rhesus macaques reside in Silver Springs State Park. Wildlife officials said they want to curb or even eliminate the monkey population because researchers said some of the animals at the park carry the herpes B virus, which could potentially spread to humans.
There have been 50 documented human cases worldwide, according to the Centers for Disease Control and Prevention. However, there have been no known transmissions to people from the Florida macaques.
Most of those who were infected had been bitten or scratched by a monkey, or when tissue or fluids from a monkey got on their broken skin. In all, 21 of the 50 died, including a researcher who was infected after bodily fluid from an infected monkey splashed into her eye.
The state of Florida wants to reduce the potential of human-monkey interaction, which is difficult since people sometimes try to feed the animals or take selfies with them.
"Whenever you talk to people when they're out, they'll say they came and visited specifically to see the monkeys," one park visitor said.
Aggressive monkeys have forced the park's closure on two occasions. In one instance, a woman visiting the park with her family said the monkeys even charged at them.
If officials want to eliminate the monkeys entirely, they'll have to remove at least half of them every other year, one 2018 study found. That would involve trapping and relocating, or trapping and euthanizing. The other option would involve sterilizing at least half the adult females every two years. That could cut the population to one-third its current size, the study showed.
But not everyone wants to get rid of the monkeys, despite the problems they pose.
"The monkeys invoke a lot of human emotion," said Steve A. Johnson, a wildlife ecology and conservation professor, and co-author of the 2018 study. He added that it's far less controversial to propose culling a non-native species like a python from Florida's Everglades. "Some people, their opinion is that these animals have a right to be there."
Are the monkeys harming Florida's environment?
The macaques, native to Asia, are one of Florida's many non-native wildlife species. While local legend says the monkeys in the park were released when the 1939 movie "Tarzan Finds a Son" was filmed in the area, experts say the primates are descended from monkeys intentionally released in the 1930s to increase tourism.
In hindsight, that was a bad idea, the researchers say.
C. Jane Anderson, a professor at Texas A&M University Kingsville and another co-author of the study, said it's not just the potential monkey-human danger that needs to be considered when managing the animals.
"We do know there's a very good chance that the macaques are having a negative impact on native species," she said. In other parts of the world, invasive macaques ate eggs of native birds and decimated bird populations. In the Florida Keys, macaques destroyed 30 acres of mangroves, said Anderson. Additionally, 3,000 free-ranging rhesus macaques are maintained on Morgan Island, South Carolina, for biomedical research, and experts blame the monkeys for elevated levels of E. coli and fecal coliform bacteria in the waterways around the island.
While the macaques may not be native to Florida, they are still a tourist attraction.
Companies offer kayak tours to see the monkeys, with tourists giving the experience five-star reviews on sites like TripAdvisor. "The monkeys were calm and accommodating," wrote one visitor, who said the troop sat on the bank of the river while people in kayaks took photos.
There might have been a reason for that: Johnson said that the monkeys are so smart that they knew that weekends drew more people to the river, and thus more opportunities for food.
"That's what makes management of them difficult," Johnson says. "They're intelligent, thinking animals."
The Associated Press and Storyful contributed to this report.