The Nile Monitor (Varanus niloticus) is quite similar to the Rock Monitor (Varanus albigularis) but can be distinguished from the latter by its more pointed snout.
The Rock Monitor has a large swollen snout and has strong, stocky limbs.
Also, the Nile Monitor grows larger than the Rock Monitor and has a long flattened tail which assists in swimming.
The tail of the Rock Monitor is longer than the body and the body is dark brown/grey with dark blotches spread across the back.
The Nile Monitor is black with yellow blotches spread across the back.
Juveniles are more vividly coloured than adults.

Chobe National Park, Botswana, 17 November 2001