The Western green mamba is a long, thin, and highly venomous snake. It is a fairly large and predominantly arboreal species, capable of navigating through trees swiftly and gracefully. It will also descend to ground level to pursue prey such as rodents and other small mammals. Some consider Western green mambas not to be particularly aggressive snakes, but others have suggested that they are extremely nervous and are prone to attack aggressively when cornered. Conflict with humans is low compared to some other species found in the region. Bites to people by this species are quite uncommon. Their mortality rate, however, is high and many of the recorded bites have been fatal.
Western green mambas are native to West Africa. They occur from Gambia and southern Senegal to Benin, including the intervening countries (from west to east) Guinea-Bissau, Guinea, Sierra Leone, Liberia, Cote d'Ivoire (Ivory Coast), Ghana, and Togo. These snakes live mainly in the coastal tropical rainforest, thicket, and woodlands. They inhabit areas where the tree cover has been removed, providing that sufficient hedges and thicket remain. They can also be found in some suitably vegetated suburbs, towns, and parklands.
Western green mambas are solitary and communicate with each other only during the mating season. They are mostly diurnal but may be active at night as well. Although they are arboreal, they do commonly go to the ground. In fact, they are equally at home hunting and feeding on prey on the ground or in trees. These snakes pursue their prey, striking rapidly and often until the prey succumbs to the venom. When they want to sleep they seek out tree branches that offer dense cover. Western green mambas are very quick, extremely agile, alert, and nervous snakes. When confronted they will quickly attempt to escape (usually up a tree if possible) and avoid any sort of confrontation. If cornered, they are highly dangerous and will show a fearsome display of aggression, loudly hissing and striking repeatedly.
Western green mambas are carnivores. They feed mainly on birds and small mammals, including rodents such as mice, rats, and squirrels. Other mammals include bats, tree pangolins, and shrews. They also eat lizards, frogs, and bird eggs.
Female Western green mambas lay up to 14 eggs placing them in rotting trunks or bury in the ground. The incubation period usually lasts 66-88 days. The young hatch green in color and measure 350-440 mm (13.7-17 in) a length. Their first molt occurs in 12-17 days.
There are no major threats to Western green mambas at present.
According to IUCN, the Western green mamba is locally common throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.