The western green mamba is a fairly large and predominantly arboreal species, capable of navigating through trees swiftly and gracefully.

Its venom is a highly potent mixture of rapid-acting presynaptic and postsynaptic neurotoxins (dendrotoxins), cardiotoxins and fasciculins.

The western green mamba was first described by the American herpetologist and physician Edward Hallowell in 1844 as Leptophis viridis, from a specimen collected in Liberia.

[6] In 1852, Hallowell described Dinophis hammondii from two specimens of western green mambas collected in Liberia, naming it for his friend Ogden Hammond of South Carolina.

[13] The long thin head has a distinct canthus above the medium-sized eyes, which have round pupils and yellowish brown irises.

[14] When threatened or otherwise aroused, the western green mamba is capable of flattening its neck area into a slight hood.

[18] The western green mamba has 13 rows of long and thin dorsal scales at midbody, fewer than any similar species.

[16] The western green mamba is native to West Africa from Gambia and southern Senegal to Benin, including the intervening countries (from west to east) Guinea-Bissau, Guinea, Sierra Leone, Liberia, Côte d'Ivoire (Ivory Coast), Ghana, and Togo.

The species persists in areas where the tree cover has been removed, providing that sufficient hedges and thicket remain.

[22] In Togo, however, its range extends into the drier open forests of the north, the Guinean savannas of the west, and the littoral zone.

The conservation status of this species was last assessed in July 2012 and published in 2013, and it was classed as such due to a wide distribution, fairly generalist habits, stable population and the lack of major threats.

The extraordinary speed with which the venom spreads through tissue and produces rapid manifestations of life-threatening symptoms is unique to mambas.

Common symptoms of a bite from a western green mamba include local pain and swelling, although uncommon, local necrosis can be moderate, ataxia, headache, drowsiness, difficulty breathing, vertigo, hypotension (low blood pressure), diarrhea, dizziness, and paralysis.

All symptoms worsen and the victim eventually dies due to suffocation resulting from paralysis of the respiratory muscles.

[24] Standard first aid treatment for any bite from a suspectedly venomous snake is the application of a pressure bandage, minimisation of the victim's movement, and rapid conveyance to a hospital or clinic.