Nairobi Arboretum #3: Monkey Talk
The cache, a small custom-made, blackened bottle-tops cache is hidden at about knee at the side of the trail in a hole under bark pieces height on the left side of the multi-forked largest tree in the area.
To reach the cache location: from the Nairobi city centre, make your way to the Uhuru Highway/University Way roundabout @ S01 16.906 E36 48.896. Turn west here and continue a short distance to the next junction at the start of State House Drive. Turn right onto the drive and continue some 1.2km to the junction with the Arboretum access road @ S01 16.652 E36 48.364. Turn off here and continue to the end of the road and then left into the parking area @ S01 16.716 E36 48.182 adjacent to the Arboretum entrance. Parking is Kshs 50 and entry is free! Once inside the park, you can make your way to the cache location by multiple routes - ideally via one or more of the other caches!
Continued from GC6CKD4 Nairobi Arboretum #5: Cheeky Monkey?! . . .
The most significant studies done on vervets involve their communication and alarm calls, specifically in regard to kin and group recognition and particular predator sightings. Anti-predatory alarm calls are important for social animals to alert others of approaching predators. Without the presence of 'language', some non-human primates (such as vervets) are known to give out different predator-specific alarm calls to alert the other members of their social group. These calls are are typically high frequency because they are harder to locate by predators. If an individual successfully alert its social group of approaching predator yet does not reveal its location, it will significantly decrease the chance of the caller to be detected and increase the chance of its social group to avoid predation.
Three well-documented vervet monkey alarm calls are those for leopard, martial eagle and python (see video here and the alarm calls chart in the 
Gallery). Different alarm calls evoke different responses to individuals that heard the alarm calls. However, the first reaction of a vervet is to look at the direction of the caller as this provides clues as to why the alarm calls were made and also where the caller is facing shows the direction of the approaching predator.
With a leopard alarm calls the vervets run up into the tree to avoid being ambushed by the leopard. Also, they sit on branches furthest away from the trunk because, even though leopards can climb trees, the branches could not support the leopard’s weight. With an eagle alarm call is given, they look up, run for the nearest bush or both to avoid an approaching aerial attack. With python alarm calls they stand bipedally and scan down on the ground.
Adult vervets are more discriminatory when eliciting alarm calls. Infants and juveniles calls however, are less discriminating and attribute most terrestrial mammals with leopard calls, flying birds with eagle calls and stick-like figures with snake calls (although, compared to infants, juveniles are more discriminant when making alarm calls). In spite of that, adult vervets seem to elicit eagle alarm calls to different species of raptors and non-raptors (see illustration in Galley). It may be concluded that adult vervets attribute eagle alarm calls to birds with the same silhouette as martial eagles. As the monkeys get older, they have a better association between predator species and types of alarm calls. Consequently vervet monkeys generally pay more attention to adult alarm calls than those of juveniles or infants.
Because they are small, easily handled, non-endangered, evolutionarily closely related to humans, and easily bred in captivity, vervets are a popular species for use in biomedical primate research. Specifically, they are important in studying high blood pressure and AIDS. They are one of the few species of non-human primates that naturally develops high blood pressure, and simian immunodeficiency virus (SIV), the ancestor of human immunodeficiency virus (HIV), is widespread throughout wild populations. There is compelling evidence that SIV was transferred from monkeys or apes in Africa to humans and led to the emergence of HIV/AIDS in humans. Studying naturally occurring SIV and the origins of HIV/AIDS in vervets and other African primates may help scientists discover a cure or vaccine for the disease.
See here for a comprehensive and fascinating vervet factsheet and here for 'Can monkeys talk?'
Listen here to vervet alarm vocalisations.