During the last year, our observations of a samango (Cercopithecus albogularis/mitis labiatus) and vervet (Chlorocebus pygerythrus pygerythrus) troop at one of our sites, has shown that the two troops have formed an alliance; predator protection appears to be enhanced as they forage together on occasion (although their diet requirements are different, they do sometimes enjoy the same food source, for example, Ficus Craterostoma in this case). Our findings echo those observed in the blue monkey.
The blue monkey (Cercopithecus mitis) that is found in Central and East Africa, ranging from the upper Congo River basin east to the East African Rift and south to northern Angola and Zambia are known to form alliances with other species which last for several hours at a time (Rudran, 1978). These associations allow the group to form coalitions against other groups, locate food sources and provides protection against predators. These alliances also the monkeys to cover large areas while foraging (source: https://animaldiversity.org/accounts/Cercopithecus_mitis/).
Not wanting to disturb the samango and vervet monkeys (Cercopithecus albogularis labiatus and Chlorocebus pygerythrus pygerythrus) crossing the paddock to reach the Forest Fig (Ficus craterostoma), we sat over fifty metres away with our cameras.
I slowly moved closer, set up the tripod and looked through the viewfinder. Almost instantly an adult male vervet perched in the highest tree began to warn the others, convincing me to move back again.
When observing this troop initially, their behaviour suggested they had seen the darker side of humans, causing them to be particularly fearful. This factor makes it difficult to get close enough for great photos.
A man herded two horses and two donkeys into the paddock which was now completely devoid of any monkey presence.
Both vervets and samangos headed across the open paddock towards the fig tree.
Above: Adult male vervet monkey keeps a look out while samangos feed. August, 2019. Dargle Valley, Kwazulu Natal.
Differences between the vervet and samango:
Habitat: The vervet monkey inhabits savanna, riverine woodland, coastal forest mountains and is often seen on the edge of indigenous forest where their range may overlap with the range of samango monkeys. Although the Samango monkey is often described as South Africa’s only primate “found exclusively in forests”, sightings of them foraging on the ground are not rare.
There are considerable differences in the diet of samango monkeys and vervet monkeys and these two species have different habitat requirements. These differences are reflected in the gut anatomy which relates to diet (see below).
The samango troop and vervet troop pictured here are sometimes seen in close proximity to each other at our study site which is made up of both indigenous forest and agricultural land.
The vervet monkey has a multi-male social system in comparison to the samango monkey’s one male social system hence one reason for the two troops foraging together may be that the multi-male vervet troop brings added protection to the samango troop which consists of adult females, one male and their youngsters.
Video footage of vervets and samangos interacting can be viewed below: