This is by far the largest venomous snake in Africa with a maximum length of 4.5 m (specimens over 3.8 m are rare). Despite its reputation it is a shy, elusive snake that is quick to escape but will not hesitate to strike repeatedly if cornered.

It is active during the day, often basking near a hole in an anthill or large rock crevice where it quickly disappears into if disturbed.

The Black Mamba is rarely black in colour. Its overall colour is usually olive green, dark olive, greyish brown, light grey or gunmetal grey, sometimes with darker mottling that may form oblique bars down the sides. But some old individuals may well be very dark in colour and from a distance may appear to be black. Juveniles are mostly light to medium grey in colour with a light belly. The inside of the mouth of a Black Mamba is usually a dark inky black (occasionally individuals with a light coloured mouth are encountered) When threatened, the snake is quick to draw back into a striking position, may form a narrow hood and open the mouth to expose the black interior.

The venom of this snake is potently neurotoxic and may cause difficulty with breathing within half an hour. Symptoms include a numbness of the lips, slurred speech, ptosis and progressive weakness. Antivenom is effective but often required in large quantities (10 – 15 vials).