The Western Green Mamba (Dendroaspis viridis), or also known as the West African Green Mamba or Hallowell’s Green Mamba, is a long, thin and highly venomous arboreal snake of the family Elapidae.
The Western Green Mamba is the second longest of the mamba genus and is the largest of the arboreal mambas - it is smaller than the Black Mamba, but larger than the Eastern Green Mamba and the Jameson’s Mamba. Adults average around 1.8m (5.9ft) though specimens that are 3.2m (10ft) have been found. This means this species, along with the Forest Cobra, is tied as the second longest venomous snakes in Africa (the Black Mamba holds first place).
This species is mostly diurnal, but may be active at night as well.It is an arboreal snake, but it does commonly go to the ground. In fact, it is equally at home hunting and feeding on prey on the ground or in trees. When it wants to sleep it seeks out tree branches that offer dense cover. It is a very quick, extremely agile, alert, and very aggressive and nervous snake.When confronted it will quickly attempt to escape (usually up a tree if possible) and avoid any sort of confrontation.If cornered, the Western green mamba is highly dangerous and will show a fearsome display of aggression, loudly hissing and striking repeatedly.