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.

1st, 2nd & 3rd photo: A juvenile. Mweya area, Queen Elizabeth National Park, Uganda, 23 January 2025
4th & 5th photo: An adult. Kazinga Channel, Queen Elizabeth National Park, Uganda, 23 January 2025