In 1979, an old DC-3 transport plane landed at a Marine Corps base near Beaufort, South Carolina. On board was an extremely unusual cargo, which even the military who served at the base came to see the unloading. Many boxes filled with screaming monkeys were carried out of the plane. The next morning they were loaded onto boats and sent to the uninhabited island of Morgan, located off the coast of the state. Now it is completely closed to outsiders, because animals that have arrived and founded a large colony here can be deadly to humans. At the same time, they are also consumables for biological experiments and play an important role in the multibillion-dollar pharmaceutical business. We explain why visiting Monkey Island is strictly prohibited.
Monkeys are completely atypical animals for both Americas (unless, of course, you count individuals kept in zoos and people). Apart from humans, this part of the world is inhabited by only one species of primate, the so-called broad-nosed monkeys, who apparently got there by making an incredible journey from Africa across the Atlantic Ocean on rafts of plants or, possibly, logs, and managed to establish a viable population. At the same time, the northern border of their habitat is in the jungles of southern Mexico, that is, for example, in the United States, colonies of monkeys in the wild are not found at all (with a couple of exceptions).
In the 1930s, Colonel S. Tui, the owner of a pleasure boat that took tourists along the small Silver River in central Florida, decided to add impressions to his guests and arbitrarily landed several monkeys on one of the river islands. The emotions of tourists remained unknown, but the monkeys liked the new place so much that they began to multiply rapidly and eventually fled from the island. The enterprising shipowner did not take into account one factor: rhesus monkeys can swim.
What kind of macaques are they and what does Rhesus have to do with it?
Rhesus macaques, or Bengal macaques, are one of the most famous and numerous species of monkeys. If you have seen monkeys occupying Thai temples or even some Asian cities, then you are most likely familiar with Rhesus. They are unpretentious, live in large flocks, willingly give birth to offspring, protect their families, and in general are quite prosperous as an animal species. In the second half of the 18th century, the French naturalist Jean-Baptiste Odbert named them Rhesus in honor of the Thracian king Res, who fought on the side of Troy during the Trojan War. In Latin, the main language of animal systematization, the king’s name was written as Rhesus.
As it turned out later, Rhesus turned out to be very suitable heroes for a variety of medical and biological experiments – from vaccine testing to organ transplantation. They also participated in the research of blood serum, thanks to which the Rh factor system was discovered. But in general, the unfortunate macaques have become one of the most popular experimental animals, which even required them to be bred on an industrial scale.
Of course, it was always possible to bring the required number of macaques from their natural range, but this increased the cost of each individual, moreover, at some point, exporting countries (for example, India) began to impose restrictions on the purchase of monkeys. Therefore, sometimes Rhesus colonies were created where it was possible to resettle them in more or less familiar conditions, but outside the original habitats. This appeared, for example, on the island of Puerto Rico, a territory dependent on the United States in the Caribbean.
However, the close coexistence of macaques and humans became a problem. So, from the same Caribbean primate research center in Puerto Rico, rhesus constantly escaped, as a result of which it was decided to transfer the research laboratory somewhere to a desert island: these monkeys were able to infect people with a dangerous disease, which prompted the final transfer of the local colony off the coast of South Carolina, on Morgan Island.
Probably the only drawback of Rhesus is that a significant part of their population is a carrier of its own variety of the herpes virus. In the macaques themselves, Macacine alphaherpesvirus 1, or herpes virus B (after the first letter of the name of the first victim, who was bitten by a monkey and died from the consequences), causes symptoms similar to ordinary human herpes. However, if it enters the bloodstream of a person as a result of a bite (or if the rhesus saliva enters the human body in any other way), this variation of monkey herpes can cause severe disorders of the central nervous system – for example, encephalitis.
It should be noted that the risk of infection is low. For example, in the natural habitats of animals, cases of infection have not been recorded at all. Virtually all macaques have antibodies to their disease, and only a small percentage shed viruses at any given time. Even a bite does not imply an indispensable infection. In the entire history of the Florida rhesus colony, 18 cases of bites were recorded, and in none of them did human infection with monkey herpes occur. True, there is another “but”. If infection does occur, the consequences are likely to be severe. The lethality of monkey herpes among humans in the absence of timely treatment is 80%. That is why measures are being taken to reduce the Florida rhesus colony (through trapping and sterilization of animals), and it was decided to isolate the former Puerto Rican group during the resettlement.
The area of the island exceeds 1800 hectares, but most of this territory is occupied by swampy meadows and channels. In one part of the Morgan there is a 250-hectare forested hill, and this area is quite enough to accommodate the population. Rhesus quickly settled in South Carolina. In 1979, approximately 1,400 individuals were resettled here, by now their number exceeds 4,000. On average, 750 cubs are born here every year, so Charles Rivers Laboratories, which received from the State Department of Natural Resources the right to lease this area. Despite the protests of wildlife advocates, rhesus are still used for biomedical purposes, albeit not on the same scale as before.
However, otherwise the monkeys feel at home in places where they have never lived. They feed on acorns, insects, mollusks, and plants, although there are not enough natural resources for the entire population. The island has a special building for the caretakers of the laboratory, who feed the animals as needed. Only they and scientists who have received the appropriate permission, evaluating the development of the colony and its impact on the vegetation of the island, are allowed to land on the Morgan coast – naturally, after taking all security measures, because the chance of contracting herpes B, although small, still exists, which means there is and mortal risk. Ordinary people are only allowed to view the monkeys from the water, passing by on a boat. On sunny days, rhesus willingly go ashore, doing everything that wild monkeys are supposed to do, and delighting outside spectators. By the way, despite the fact that monkeys can swim, only single shoots to the “mainland” have been recorded. Apparently, the macaques are still happy with everything in the place, which, as they think, belongs only to them.