© Sofia Forsse
The Study site
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The Urban Vervet Project is based at the Simbithi Eco-Estate, a privately owned residential community that is 430ha in size situated in Ballito at the East coast of South Africa. The estate is found in the southern part of the KwaZulu-Natal province and is a half hour drive to King Shaka International Airport in Durban and about a 7-hour drive from O.R Tambo International Airport in Johannesburg. The estate is currently owned by Rosemary Ladlau, Mayvis Nhleko, Joseph Jobe, and managed by a board of directors.
The Simbithi estate is a green and lush eco-friendly residential complex, where human structures such as houses, community centres, gold course and roads alternate with park areas and human engineered natural patches made up entirely of indigenous plant species. Beyond humans, Simbithi also provide a home for a vast array of wildlife, including our study system the vervet monkeys. The coastal climate at this site is largely humid and tropical with annual rainy periods from October to March alternated with somewhat drier and very hot summertime. Average temperatures during the day range from 5°C in wintertime (Jun-Jul-Aug) to 35°C in summertime (Jan-Feb-Mar). However, nights can be cold, and temperature can occasionally drop to 0°C in wintertime. |
Vervet MOnkeys
Vervet monkeys (Chlorocebus pygerythrus) are a species of Old-World monkey found throughout sub-Saharan Africa. They are one of the most prolific primate species in Africa together with baboons that have adapted to a diverse range of habitats ranging from agricultural landscapes, tourist parks and cities. In the Anthropocene they became a familiar inhabitant alongside humans, triggering research of great importance for our understanding of how human modified ecosystems impact primate species, such as the vervet monkeys. UVP aims at generating critical knowledge necessary to predict the ongoing impacts of urbanization on current and future primate populations to facilitate harmonious co-existence. Vervet monkeys are semi-arboreal, spending a significant portion of their day on the ground (1) (Cheney & Seyfarth, 1990)[SF1] . Troops occupy home ranges and move around these ranges throughout the day to forage (2) (Isbell et al, 1990). Vervet monkey live in social units composed of multiple males and multiple females, with males dispersing at sexual maturity whilst females remain in their natal troops throughout their lives (3)(Cheney & Seyfarth, 1983). Females first reproduce at around four years of age, and at most sites exhibit yearly reproduction cycles (one baby per female per year), with the birth season lasting roughly from September to December in South Africa. Vervet monkeys are opportunistic and omnivores, eating a variety of plant species, as well as invertebrates and some vertebrate preys and anthropogenic food sources (4-6)(Struhsaker, 1967; Whitten, 1988, Felsch et al. 2025).
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© Sofia Forsse
UVP/Simbithi Monkey groups
Simbithi Eco-Estate is home to multiple groups of vervet monkeys, in a monkey survey 2025 the total group number was estimated to be 11, some groups occasionally ranging outside the Simbithi estate, with an estimated average group size of 25 monkeys. Vervet groups fluctuate in number overtime due to birth season, immigration between groups and mortality rates, which in our case is due to both natural causes and human impacts (such as traffic). Within the scope of detailed individual-level data collection at UVP we currently follow two habituated troops: Savanna & Pink representing a larger troop and an average size for Simbithi conditions. UVP monitors the two groups daily and collects detailed data on their demography, life history, behaviour and ranging behaviours. Through detailed, individual level-based approach, using both focal follows and Ad libitum protocols, we are capturing high-resolution profiles on the monkeys’ foraging behaviours, social relationships, vocalisations, and many more factors involved in how they use and adapt to the urban landscape. Our two study groups have overlapping territories primarily located along the roads of Acacia drive and Ladlau drive. In the first years of the project, we also tracked another group (Acacia) in great detail, and we continue our broader monitoring of them as well as other Simbithi groups. Some of the other neighbouring groups sometimes interact with our groups, yet not all of them are habituated to be followed closely by human researchers. In our habituated groups, all vervet monkeys are individually identified, allowing us to monitor the composition of the group daily, and all social interactions between the individuals as well as importantly their development over time and distinct personalities.
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Pink - N=37
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Savanna - N=25
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© Stephanie Mercier & Lindsey Ellington
Other simbithi wildlife
Simbithi is a place of abundant natural beauty with a long list of African wildlife. The Simbithi estate host antelopes such as duikers (grey, blue, and red), bushbucks, and reedbucks. Also, smaller mammals can be observed here, including porcupine, multiple mongoose species such as water mongoose, slender and banded mongooses and spotted genet. Two primate species are present: bushbabies and vervet monkeys (of course). In addition, Simbithi is home to many stunning bird species (over 300 species!). Reptiles are represented over a few species of tortoises, marsh terrapins, lizards, skinks, monitor lizards and chameleons as well as multiple snake species (ca. 20 species), including mambas, cobras, pythons, boomslang, vinesnake, spotted bush snake and brown house snake. Some snakes at the estate, such as the African rock python count towards potential predators to the vervet monkeys we study here, together with occasionally observed raptors like eagles, and the abundant number of domesticated dogs.
© Stephanie Mercier
UVP fieldwork
Simbithi is a safe place to be and conduct research for our team. Researchers all live together in Dr. Forss rental flat within Simbithi. Compared to more “traditional” field site settings, UVP accommodation is quite luxurious, provides our team with hot running water, electricity, mobile phone reception and WIFI with good internet connection. We study and collect detailed behavioural data on the Simbithi monkeys between sunrise (locating the monkeys at their sleeping sites) and sunset. Simbithi is safe enough so that our team members can work alone and target different monkey troops throughout the day. UVP long-term data collection encompass multiple methodological paradigms, ranging from focal follows, detailed Ad libitum behavioural data, social scanning, GPS tracking and a wide range of behavioural and cognitive experiments. We currently monitor with great detail two monkey troops and maintain a broader tracking of multiple co-residential troops. Simbithi monkeys share their habitat with human residents, ranging through their gardens (and entering their houses) bringing us as researchers also close to our Simbithi human residents. UVP works closely with both parties. As such, our team follow the monkeys for a minimum of 6-8 hours daily, working 5 days per week in the field, avoiding weekends as we are considering their privacy and do not want to disturb during leisure times
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© Sofia Forss
