The monkey island was the brainchild of several scientists—notably Clarence Ray Carpenter, considered by many to be the grandfather of American primatology. From the 1930s onward, Carpenter traveled around the world studying howler monkeys in Panama and gibbons and rhesus macaques in Southeast Asia, and he was among the first to film these animals in the wild. Carpenter and his colleagues had a vision of establishing a free-ranging colony of these animals closer to home, where they could be studied more easily, and eventually be used for research.

And so, in 1938, Carpenter took some 500 rhesus macaques on a 51-day voyage from Calcutta to Puerto Rico, via Colombo, Boston, and New York. He single-handedly cared for the animals, which, as he later wrote, “covered the deck of a large freighter.” Most survived, and some were sold to a research institute to cover the exorbitant costs of the expedition. Some 406 were eventually released on Cayo Santiago. A year later, they were joined by 14 gibbons, but these apes, which typically swing through the canopies of Asian rainforests, didn’t take to the flat, small island. They also had a habit of attacking human observers, so they were later relocated to zoos.

The macaques took time to adjust too. A few plucky individuals swam across to Puerto Rico proper. Those who stayed quickly ate all the papayas and coconut palms, forcing researchers to provision them with food. No one had built facilities for collecting rain, so workers had to ferry over drums of fresh water. But they did survive, and they started breeding. “The suspense created by doubting Thomases ... was relieved after six or eight months by the birth of the first baby,” Carpenter later wrote. “You cannot imagine how welcome that baby was.”

There are now at least a thousand of them, and researchers have since meticulously documented their lives. They trap the macaques once a year to take blood samples and check on their health. Researchers have measured their hormone levels, and sequence their DNA. Whenever the animals die, their skeletons are preserved, and thousands of such skeletons now exist in storage. “Put that together, and you have a population with such a huge amount of information from birth to death and beyond,” says Higham. “There are other free-ranging, accessible primate populations but nowhere else with this breadth and depth of data.”

The monkeys have experienced hurricanes before, including Hugo in 1989 and Georges in 1998. But these earlier storms pale in comparison to those of this exceptional season. Hurricane Irma narrowly missed them, but Maria struck them head-on.

Punta Santiago, where the staff of the Caribbean Primate Research Center live, has been destroyed. One aerial snapshot revealed a plea for help—S.O.S. necesitamos agua/comida (we need food and water)—painted on the street.

This heartbreaking message is from our flyover of #PuntaSantiago. #Humacao #PuertoRico needs a bigger response, & it needs it now. pic.twitter.com/8d7UH4vw7Q — NYU Primatology (@nyuprimatology) September 25, 2017

Three employees are still unaccounted for, and it’s hard to know everyone’s whereabouts given the collapse of the island’s roads and communications network. One staff member, Omar, who runs the boats to the island, has lost his home, cars, and all his personal belongings to the flooding. “We were on the phone yesterday trying to find out his kids’ shoe size to send them a pair of shoes,” says Santos. Friends and alumni of the center, including a who’s who of primatologists, have also raised over $14,000 to support the beleaguered community.