Habitats, ecology, and behaviour of C. aethiops are reviewed in Butynski and Kingdon (2013). This species is a diurnal, semi-terrestrial omnivore that occurs in wooded savannas, woodlands, and forest-grassland mosaics, reaching the highest densities on the edges of rivers and lakes (Butler 1966; Dorst and Dandelot 1972; Dunham and Dunham 1974; Yalden et al. 1977; Zinner et al. 2001, 2002; Fufa et al. 2020; Yitayih et al. 2021). This is an extremely adaptable monkey that is also able to survive in rural and urban areas. This often results in human-monkey conflict, particularly in relation to crop-raiding. As a result, it is harassed by people and sometimes killed (Dunbar and Dunbar 1974; Zinner et al. 2001, 2002; Fufa et al. 2020; Yitayih et al. 2021).

In the Bole Valley, fruits and seeds comprised 51% of the diet, followed by leaves (19%), flowers (18%), and insects (7%). Here, home-range size of two groups was 19.5 ha and 29.4 ha, and mean day range was 700 m. Mean size of four groups was estimated to be 19 individuals, with the largest group comprising 29 individuals (Dunbar and Dunbar 1974). In Awash National Park, central Ethiopia, groups ranged in size from 10 to 35 individuals (C.J. Jolly and J.E. Phillips-Conroy pers. comm. in Butynski and Kingdon 2013). In Eritrea, mean size of 22 groups was 9.1 individuals (range = 3–22) (Zinner et al. 2002). Composition of the subpopulation of 5,046 C. aethiops on the Zegie Peninsula was 13% adult males, 25% adult females, 36% juveniles, and 26% infants (Yitayih et al. 2021).

Chlorocebus aethiops is endemic to northeast Africa, east of the White Nile River, from northeastern Sudan southwards through eastern South Sudan, Eritrea, to southwest and central Ethiopia, to Djibouti (Butler 1966; Hill 1966; Kock 1969; Dandelot and Prevost 1972; Dandelot 1974; Yalden et al. 1977; Wolfheim 1983; Lernould 1988; Künzel et al. 2000; Zinner et al. 2001, 2002; Butynski and Kingdon 2013; Butynski and De Jong 2022). Its range formerly extended farther north along the Nile Valley to at least 19° 30’N; 33°E and, perhaps, even to southern Egypt. The current northern limit is thought to be approximately 15°N (Butler 1966, Kock 1969), which is likely the northernmost limit of any species of guenon (Butynski and Kingdon 2013).

The known altitudinal range is 0–2,600 m asl in Eritrea (Zinner et al. 2001) and 200–3,000 m asl in Ethiopia (Yalden et al. 1977, Mekonnen et al. 2012). The altitude at the northern-most site known for C. aethiops along the Nile River (19° 30’N) is about 220 m asl. Mean annual rainfall ranges from about 300 mm to 2,000 mm (Dunbar and Dunbar 1974, Yalden et al. 1977, Zinner et al. 2001, Butynski and Kingdon 2013). 

Chlorocebus aethiops aethiops (common grivet) occurs east of the White Nile River, from northeastern Sudan southwards through eastern South Sudan, Eritrea, to west and northwest Ethiopia (west of the Eastern Rift Valley), to Djibouti (Butler 1966; Hill 1966; Kock 1969; Dandelot and Prevost 1972; Dandelot 1974; Yalden et al. 1977; Wolfheim 1983; Lernould 1988; Künzel et al. 2000; Zinner et al. 2001, 2002; Butynski and Kingdon 2013; Butynski and De Jong 2022). Apparently meets C. a. matschiei along part of the southeastern edge of its range. Geographic range about 870,000 km², altitude range 0–3,000 m asl (Dandelot 1974, Yalden et al. 1977, Butynski and De Jong 2022).

Chlorocebus aethiops matschiei (Matschie’s grivet) is endemic to Ethiopia. Occurs in Kaffa Province and Shewa Province, central Ethiopia, west of the Eastern Rift Valley, and on the graben floor where it meets C. a. hilgerti (Butynski and De Jong 2022). Geographic range about 115,000 km², altitude range 440–3,000 m asl (Dandelot 1974, Yalden et al. 1977, Butynski and De Jong 2022).

Chlorocebus aethiops hilgerti (Hilgert’s grivet) is endemic to Ethiopia. Occurs in Harrar Province and Arsi Province, central Ethiopia, east of the Eastern Rift Valley and on the graben floor where it meets C. a. matschiei (Butynski and De Jong 2022). Geographic range roughly 73,000 km², altitude range 1,100–3,000 m asl (Dandelot 1974, Yalden et al. 1977, Butynski and De Jong 2022).

Chlorocebus aethiops appears to be parapatric to, and likely intergrades with, Omo vervet Chlorocebus pygerythrus zavattarii, northeastern vervet Chlorocebus pygerythrus arenaria, and djam-djam monkey Chlorocebus djamdjamensis in southern Ethiopia, and with Budgett’s tantalus Chlorocebus tantalus budgetti in southeastern South Sudan (de Beaux 1943, Lernould 1988, Butynski and Kingdon 2013, Haus et al. 2013, Wallis 2013, Gippoliti 2018, Butynski and De Jong 2022).

Chlorocebus aethiops is listed on Appendix II of CITES and on Class B of the African Convention on the Conservation of Nature and Natural Resources. Occurs in several national parks and protected areas, including Alatish National Park, Gambella National Park and Kafta Shiraro National Park Eritrea has long-term plans to create a protected area system that will include C. aethiops (Zinner et al. 2002).

Research is required to assess taxonomic status, geographic distribution, abundance, natural history, threats, conservation status, and, if necessary, priorities for conservation actions.