Vervet Monkeys - The Least Concern Primates

There has been a great amount of research on vervets in the wild since the 1960's. The main topics of research have been social organisation, male migration, group fusion and fision (Cheney & Seyfarth, 1983; Isbell et al., 1990; Isbell et al., 1991), terrestriality in non-human primates (Gebo & Sargis, 1994; Tosi et al., 2004), and above all - vocalisations (Cheney & Seyfarth, 1981; 1982; 1985; 1988; Hauser, 1988; Seyfarth et al., 1990). The alarm calls of the vervets are famous and there is a vast amount of published literature avaliable from both a primatology point of view, and an anthropological one. There have been many studies on the morphology of this species group comparing skeletal features of semi-terrestrial and arboreal primates (Cardini & Elton, 2008). There is also literature available that covers the interactions of vervets and humans in tourist areas (Brennan et al., 1985), and also in cultivated areas where the monkeys crop raid (Boulton et al., 1996).

Vervets often crop raid because of their close porximity to cultivated land and are frequently shot at by farmers. This female has lost both eyes, as well as other injuries, from shot gun wounds.

Even with all this available literature, a fully balanced representation of the situation of the vervet monkeys is lacking. This is due to a number if factors. First and foremost is the problem of their taxonomy. They have been described as one superspecies with anywhere up to 22 subspecies. They are now described as six species of a seperate genera. The majority of the field work published is from long-term studies of the population of vervets in the Amboseli National Park in Kenya (Struhsaker, 1967; 1971; 1973; 1976; Seyfarth et al., 1980; Wrangham & Waterman, 1981; Cheney & Seyfarth, 1983; Isbell et al., 1990; 1991). These populations in Kenya are now known to be the species Chlorocebus pygerythrus. Most of the crop raiding data is from studies of the green monkey (Ch. sabaeus) in the West Indies where vervets do not naturally occur, but were introduced around 300 years ago. These bodies of literature, comprehensive studies of only two of the six species, are not fully representative of the situation of the six species, over their entire distribution in all their different ranges. There is close to no data available on the Bale Mountains vervet (Ch. djamdjamensis), and very little available on the grivets (Ch. aethiops) in Ethiopia.

This young male was orphaned when he was a newborn infant. He was injured when his mother was killed and suffered nerve damage to his hand. He was brought to a rehabilitation centre where he proceeded to obsessively chew his injured hand. He eventually ceased this behaviour and now lives in a troop of other rehabilitated orphans where his missing limb does not seem to slow him down!

The majority of literature on these monkeys is from the 1960's, 70's and 80's. The Redlist status these monkeys have gained is based on data that is out of date and not comprehensive enough for each species. Political instability in many of the countries in which they occur has made censusing difficult and current population numbers are not available (Groves, 2001). The more recent literature on these species are not field studies, but biomedical research. The one recent field study does present worrying data. A survey was carried out in Côte d'Ivoire where Ch. sabaeus was thought to be common. In the five forest study sites, there was no sign of any of the study species, not even vocalisations were heard. They seem to have been exterpated from their former range (Gondelé Bi et al., 2009). What might the situation turn out to be if each species were to be censused over their entire range?

Some monkeys are often traumatised by experiences at the hands of humans, whether it is deliberate abuse, or being kept in inappropriate conditions as a pet. This female displays stereotypical self grasping behaviour.

The assumptions that there is no need to perform any conservation efforts for these monkeys is based on out of date data. They are perceived as pests in many habitat countries. Rehabilitation centres and sanctuaries receive orphans every baby season. Should we be worried about these 'Least Concern' primates?

Infant vervets are orphaned in the hundreds every year and not all are lucky enough to be brought to rehabilitation centres. They are not considered to be worth it. They are perceived as pests in many range countries. This infant female is displaying the finger sucking behaviour that is common in orphans that have been deprived of a mother from whom they would naturally be suckling.

Often when these monkeys are orphaned they are kept as pets. An inappropriate diet often leads to cateracts and eventual blindness. This female would never survive in the wild.