The Olive Grass Snake is a long thin snake, usually shiny brown in colour. The snake has elongated scales and a big eye, and often has spots on the upper lip. They are very fast snakes.
The Black Mamba’s colour varies from light olive to light grey, darkening with age to olive, grayish brown, and gunmetal grey. They also sometimes have mottling. The Black Mamba has an elongated, coffin shaped head, and in most specimens the interior of the mouth is usually inky black in colour. This snake can lift up to a third of it’s body off the ground and forms a narrow hood when threatened.
It’s easy to confuse an Olive Grass Snake with a Black Mamba. The graphics below illustrate how to recognize the key differences between the two species.