Chlorocebus is a genus of medium-sized primates of which seven species are currently recognized.
The seven species look very similar and were therefore formerly classified as a single species.
These seven species are:

1. Green Monkey (Chlorocebus sabaeus), found in West Africa;
2. Tantalus Monkey (Chlorocebus tantalus), found in Ghana to Sudan and south into Uganda;
3. Vervet Monkey (Chlorocebus pygerythrus), found in southern and East Africa.
4. Bale Mountains Vervet (Chlorocebus djamdjamensis), found only in Ethiopia;
5. Grivet (Chlorocebus aethiops), found in Ethiopia, Sudan, Djibouti and Eritrea;
6. Dryas Monkey (Chlorocebus dryas), found only in the Congo Basin; and
7. Malbrouck (Chlorocebus cynosuros), found in DR Congo, Angola and Zambia.

The one occurring in Tanzania is the Vervet Monkey (Chlorocebus pygerythrus).

Lake Manyara National Park, Tanzania, 11 January 2008