The western green mamba (Dendroaspis viridis), also known as the West African green mamba or Hallowell's green mamba, is a long, thin, and highly venomous snake of the mamba genus, Dendroaspis. This species was first described in 1844 by the American herpetologist Edward Hallowell. The western green mamba 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.