Chlorocebus is a genus of medium-sized primates from the family of Old World monkeys. Six species are currently recognized, although some people classify them all as a single species with numerous subspecies. Either way, they make up the entirety of the genus Chlorocebus.

Confusingly, the terms "vervet monkey" and "green monkey" are sometimes used to refer to the whole genus Chlorocebus, though they also refer more precisely to species Chlorocebus pygerythrus and Chlorocebus sabaeus, respectively, neither of which is the type species for Chlorocebus. This article uses the term Chlorocebus consistently for the genus and the common names only for the species.

The native range of these monkeys is sub-Saharan Africa from Senegal and Ethiopia south to South Africa. However, in previous centuries, a number of them were taken as pets by early Caribbean settlers and slave traders, and were transported across the Atlantic Ocean to the Caribbean islands. The monkeys subsequently escaped or were released and became naturalized. Today, they are found on the West Indian islands of Barbados, Saint Kitts, Nevis, Anguilla, and Saint Martin. A colony also exists in Broward County, Florida.

Taxonomy

The classification of the Chlorocebus monkeys is undergoing change. They were previously lumped together with the medium-sized arboreal African monkeys of the guenon genus, Cercopithecus, where they were classified as a single species, Cercopithecus aethiops.

Physical description

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.

Behavior and ecology

thumb|left|Male vervet monkey

Unlike the closely related guenons, Chlorocebus species are not primarily forest dwellers. Rather, they are semi-arboreal and semi-terrestrial, spending most of the day on the ground feeding and then sleeping at night in the trees. They use a wide variety of vocalizations. Many tourists have also found out these monkeys will deliver a powerful bite if they are cornered or threatened. In Africa, the documented attacks by these monkeys are extremely rare when compared with dog attacks, in spite of living very closely with humans and often being threatened by humans and their dogs.

To signal mating readiness, the female presents her vulva to the male. Since groups are made of several more females than males, each male mates with several females. Generally, the male will display a striking, light-blue scrotal pouch, most prevalent during the mating season. Males do not take part in raising the young, but other females of the group (the "aunties") share the burden. The dominance hierarchy also comes into play, as the offspring of the more dominant group members get preferential treatment. The gestation time is about 163–165 days,

In some African countries, many monkeys are killed by power lines, dogs, predatory animals e.g. wild cats, vehicles, shooting, poisoning, and hunting for sport. Added to this, an increase in desertification, and loss of habitat due to agriculture and urbanisation has occurred. As a result, the population numbers in troops are declining in urban areas to an average of between 15 and 25 individuals, with many troops disappearing altogether.

Use in scientific research and vaccine production

The African green monkey has been the focus of much scientific research since the 1950s, and cell lines derived from its tissues are still used today to produce vaccines for polio and smallpox. Chlorocebus species are also important in studying high blood pressure and AIDS. Unlike most other nonhuman primates, they naturally develop high blood pressure. In Africa, the monkeys are massively infected with simian immunodeficiency virus (SIV), related to the ancestor of human immunodeficiency virus (HIV), both of which are widespread throughout populations. Chlorocebus monkeys are a natural host of SIV and do not succumb to immunodeficiency upon infection; therefore they are an important model in AIDS studies to understand protective mechanisms against AIDS. The monkeys infected with SIV and humans infected with HIV differ in microbial responses to infection.

Vero cells are a continuous cell line derived from epithelial cells of the African green monkey kidney, and are widely used for research in immunology and infectious disease. Similar cell lines include buffalo green monkey kidney and BS-C-1.

Chlorocebus monkeys are an important model organism for studies of AIDS, microbiome, development, neurobehavior, neurodegeneration, metabolism and obesity. A genome of chlorocebus monkey (Chlorocebus sabaeus) was sequenced and the genome reference with gene models is available in genome browsers NCBI Chlorocebus_sabeus 1.1 and Ensembl Vervet-AGM (Chlorocebus sabaeus) . It facilitated genomic investigations in this monkey, including population genetics studies across Africa and Caribbean and characterization of gene expression regulation across development in brain and peripheral tissues, during prenatal development, and during reaction to psychosocial stress related to relocation and social isolation.

Epigenetic clock based on CpG methylation in DNA - a complex biomarker of aging - was developed for Chlorocebus sabaeus in several variants: tissue-specific clocks for brain cortex, blood, and liver; multitissue clock; and human-sabaeus monkey clocks.

References

Sources

  • Barbados wildlife: green monkeys
  • Primate Info Net Chlorocebus factsheet