the common night adder can grow up to around 60 centimeters (24 in) long, making it the longest species of the genus "causus". the longest ever recorded was a male found in eastern zimbabwe which was 93 centimeters (around 37 in) long. they are usually olive green, brown, or grayish-brown in color with black rhombic-shaped blotches, but not all have blotches on them.