The Tantalus Monkey is an Old World monkey which traditionally ranges from Senegal and Ethiopia to South Africa. More recently, a number of them were carried by slavers to the Caribbean islands, along with enslaved Africans. The monkeys subsequently escaped or were released and became naturalized. The descendents of those populations are found on West Indian islands and even in Florida. The dorsal fur of Chlorocebus monkeys varies by species from pale yellow through grey-green brown to dark brown, while the lower portion and the hair ring around the face is a whitish yellow. Males have a blue scrotum and red penis and weigh from 3.9 to 8 kg while females weigh from 3.4 to 5.3 kg. Their births usually happen at the beginning of the rainy season, when there is sufficient food available. The life expectancy of the green monkeys is 11-13 years in captivity, and about 10-12 years in the wild. They eat leaves, gum, seeds, nuts, grasses, fungi, fruit, berries, flowers, buds, shoots, invertebrates, bird eggs, birds, lizards, rodents, and other vertebrates. Their preferred foods are fruit and flowers, a seasonal resource that is varied to cope with changes in food availability. In tourist areas, they will commonly steal brightly coloured alcoholic drinks left behind by tourists. They use a wide variety of vocalizations; they warn off members of other groups from their territory, and also warn members of their own troop of dangers from predators, using different calls for different predators. Facial expressions and body posturing serve as additional communication tools in a highly complex set of social interactions. Where alliances can be formed for benefit, deception is sometimes used. Although they are not endangered, their numbers are declining due to powerlines, dogs, vehicles, shooting, poisoning, and hunting, both as a food source and as a source of traditional medicines. Added to this, there is an increase in desertification, and loss of habitat due to agriculture and urbanisation. As well, they have been the focus of much scientific research since the 1950s, and they are used to produce vaccines for polio and smallpox, and in studying high blood pressure and AIDS.