KEY LOIS, Fla. -- The once-lush shoreline of this tiny island is an eerie tangle of dead, gnarled wood. The clear blue water is fouled a muddy brown. Well-fed monkeys roam along the barren beach, past a row of red mangrove trees.
It is the trees, not the monkeys, that are in cages.
For deep in the Florida Keys, monkey business has given way to munching mayhem.
Here, on a key of 100 acres, more than 1,500 rhesus monkeys romp and scurry and swing and chase and scream. Under the tropical sun, they hang from branches, stroll down a boarded walkway, scout the waterfront, fight, play, dally and, perhaps most notably, dine.
They are the key's only inhabitants. Most of them have free rein. But they evidently became bored a long time ago with this pristine piece of paradise.
Or maybe they got tired of Purina monkey chow.
Because in the 18 years since Charles River Laboratories, a subsidiary of the optical giant Bausch & Lomb, began raising them for sale as research animals, the monkeys have ravaged so many red mangrove trees that environmentalists compare the defoliation to Vietnam after Agent Orange.
"These monkeys are running around, defecating, killing protected mangrove trees -- on public land," said Curtis Kruer, a biologist who worked for the U.S. Army Corps of Engineers for nine years and is the vice president for conservation of the Florida Keys Audubon Society.
Or, as the supermarket tabloid The Star proclaimed last fall: "Sex-mad Monkeys Tear Apart Florida Island."
The uncivilized behavior of the monkeys has reached the civil courts of Florida, where the state and the company are debating whether the monkeys are wrecking public or private land on Key Lois and nearby Raccoon Key, where Charles River keeps 2,200 more primates for breeding.
Welcome or not, the monkeys have made themselves at home.
Some climb the same trees they have destroyed, sit on tall, leafless stumps and stare out far into the blue ocean. Others scamper across squat gray skeletal remains of mangrove bushes, ducking under one branch, hurdling another.
They are small animals, no more than 40 pounds, with cinnamon-brown fur and blond bellies, their fleshy faces lined and alert.
They show no remorse. Or concern.
The fuss comes from neighbors and environmentalists. (The animal-rights folks haven't weighed in on this one yet.)
One recent afternoon, Mr. Kruer motored his small boat toward the shore, past a single monkey atop a lonely tree. Mr. Kruer paused to look beyond the dingy beach, where wire cages secure whatever grows in the soil beneath them.
The biologist squinted into his binoculars.
"There's not even mangroves in any of those cages," he said, disgusted.
Just down the shore, however, were a good many monkeys, bursting in and out of a feeding pen, scooting along twisted tree trunks, wandering the beach. One scrounged around until he found a purple wrapper that had washed up with the surf. The monkey chewed it.
"It's my understanding," Mr. Kruer said, "that they eat almost anything. The company doesn't want to admit that because it makes their case look bad: Monkeys are eating the island."
The company says, in its defense, that mangroves were considered a weed when it opened its first monkey colony in 1973 and that it had no idea the monkeys, native to India, would maul red mangroves the way they did. The animals are used for biomedical research by pharmaceutical firms and government agencies, aiding in the testing of vaccines and drugs.
"I think the damage is significant to that particular island, but I think everything has its mitigating circumstances and the value of these monkeys offsets or outweighs the damage," said Paul Schilling, director of primate breeding operations for Charles River.
To spare remaining mangroves, the state is requiring that all the monkeys be rounded up and caged during the next 20 years. No one has figured out another way. Everyone agrees the company's idea of caging the trees has its, well, limits.
State biologists consider the red mangrove trees vital to the ecology of the Florida Keys, recently designated a National Marine Sanctuary. The trees, with their sprawling branches and waxy green leaves, grow partly submerged in water in keys and are valued for keeping shorelines intact and water clear for coral. They also shelter birds and fish, and feed organisms with their decomposed leaves.
Since 1985, it has been a crime in Florida to destroy mangroves.
But what if the hoodlums are lower primates?
Former Gov. Bob Martinez angrily vowed last summer that the state would try to prosecute Charles River Laboratories. That did not happen. But the land battle went into civil court.
All the while, the monkeys have shown a distinct taste for the red mangrove. Each day, workers lug them fresh water and a half-ton of Purina monkey chow. They have eaten their chow -- and the red mangroves. This, while they have snubbed black mangrove trees, which grow thick (but with salty leaves) in the center of both keys.
So why do the monkeys savor red mangroves? Boredom? Gluttony? Low-salt diets?
"Everyone has a theory," said Mr. Schilling of Charles River Laboratories, "but no one knows what goes on in monkeys' minds."
If the motive is unclear, the digested result is outright murky.
"They're letting the effluent from a thousand monkeys go in the [ocean] water there," said Dagny Johnson, president of the Upper Keys Citizens Association. "Monkey refuse is like human refuse, you know."
Except that the ocean disinfects it, said Mr. Schilling. Moreover, in a year, the waste of monkeys in cages (now less than 25 percent) will be treated with a sewage system, he said.
"We could potty-train them," Mr. Schilling added, "but I think that would be impossible at this point, monkeys being monkeys."
Anti-monkey residents, however, think the solution is to find the monkeys a suitable home -- and find it before one much-discussed disaster scenario comes to pass.