Common night adder

The common night adder is a species of venomous vipers found in sub-Saharan Africa. 
Description.
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.
Common names.
The common night adder is also called the "rhombic night adder", the "demon night adder", the "Cape Viper", and the "African night adder".
Where they live.
The common night adder is found in the savannas of Sub-Saharan Africa, from Nigeria, east to Sudan, Ethiopia, Somalia and Kenya, south to Tanzania, Uganda, Rwanda, Burundi, Democratic Republic of Congo, Angola, Zambia, Malawi, Zimbabwe, northern Botswana, Mozambique, Swaziland, and eastern South Africa.
Behavior.
The common night adder is a fairly fast species of snake; it can move at the speed of 3.3 km per hour. They are usually found on the ground, but they can climb trees and can swim. They are mainly nocturnal, but some have been seen basking in the early morning or late afternoon. When disturbed they coil up, inflate their body (which makes the black blotches on them stand out), and start hissing loudly.
Common night adders are oviparous, meaning that they lay eggs, while other vipers are usually viviparous, meaning that they give live birth. Females lay around two dozen eggs at a time, which take around four months to hatch. Once hatched, the young are 10 to 12.5 cm long and eat small frogs and toads.
Feeding.
Their diet is made up of mainly frogs and toads, and sometimes small mammals like mice and rats.