Jameson's mamba

Jameson’s mamba (Dendroaspis jamesoni) is a highly venomous snake from the Elapidae family, found across equatorial Africa. It belongs to the mamba genus Dendroaspis and is a slender species, with dull green upperparts and a cream belly. Adults typically measure between 1.5 and 2.2 meters in total length. Scottish naturalist Thomas Traill first described it in 1843, and today two subspecies are recognized.

Venom

The nominate subspecies lives in central and western sub-Saharan Africa, while the eastern black-tailed subspecies inhabits eastern sub-Saharan Africa, mainly western Kenya. This snake is mostly arboreal, feeding primarily on birds and mammals. Its venom contains both neurotoxins and cardiotoxins. In humans, a bite causes pain and swelling at the site, followed by chills, sweating, abdominal pain, and vomiting.

Later symptoms include slurred speech, difficulty breathing, and paralysis. Fatalities have occurred within three to four hours of the bite. The venom of the eastern subspecies is roughly twice as potent as that of the nominate form. Thomas Traill, a Scottish doctor and zoologist, first described Jameson’s mamba as Elaps jamesoni in 1843.

Taxonomy and etymology

The species name honors Robert Jameson, a contemporary of Traill and the Regius Professor of Natural History at the University of Edinburgh, where Traill studied. In 1848, German naturalist Hermann Schlegel created the genus Dendroaspis, designating Jameson’s mamba as the type species. The genus name comes from the Ancient Greek words dendron (tree) and aspis (asp). French zoologist Auguste Duméril misspelled the genus as Dendraspis in 1856, and this error persisted until Dutch herpetologist Leo Brongersma corrected it in 1936.

That same year, British biologist Arthur Loveridge described a new subspecies, D. jamesoni kaimosae, from a specimen collected in Kenya’s Kaimosi Forest. He noted it had fewer subcaudal scales and a black tail instead of a green one. Analysis of mamba venom places Jameson’s mamba as the sister species to the western green mamba (Dendroaspis viridis). Jameson’s mamba is long and slender, with smooth scales.

Description

The tail makes up about 20 to 25 percent of the total length. Adults reach about 1.5 to 2.2 meters, though some grow as large as 2.64 meters. Males and females are generally similar in size, though fieldwork in southeastern Nigeria found males significantly larger. The back is dull green, fading to pale green on the belly, with scales often edged in black.

The neck, throat, and underparts are usually cream or yellowish. The head is narrow and elongated, with small eyes and round pupils. Like the western green mamba, it can flatten its neck when threatened. The eastern subspecies (D. jamesoni kaimosae) has a black tail, while central and western individuals typically have a pale green or yellow tail.

Scalation

The thin fangs are attached to the upper jaw and have a furrow running down the front. Scale patterns help identify the species. Jameson’s mamba has 15 to 17 rows of dorsal scales at midbody, 210 to 236 ventral scales (subspecies jamesoni) or 202 to 227 (subspecies kaimosae), 94 to 122 divided subcaudal scales (jamesoni) or 94 to 113 (kaimosae), and a divided anal scale. The mouth has 7 to 9 supralabial scales (usually 8) above and 8 to 10 sublabial scales (usually 9) below, with the fourth scales positioned over and under the eye.

Each eye has three preocular, three postocular, and one subocular scale. Jameson’s mamba is found mostly in Central, West, and parts of East Africa. In Central Africa, it ranges from Angola north through the Democratic Republic of the Congo, Republic of the Congo, Central African Republic, and into the Imatong Mountains of South Sudan. In West Africa, it occurs from Ghana east to Togo, Nigeria, Cameroon, Equatorial Guinea, and Gabon.

In East Africa, it is found in Uganda, Kenya, Rwanda, Burundi, and Tanzania. The subspecies D. jamesoni kaimosae is endemic to East Africa, mainly in western Kenya (its type locality), as well as Uganda, Rwanda, and adjacent parts of the Democratic Republic of the Congo. The species is relatively common and widespread, especially in its western range. Fieldwork in Nigeria suggests it is sedentary.

It lives in primary and secondary rainforests, woodland, forest-savanna, and deforested areas up to 2,200 meters in elevation. Adaptable, it persists in areas with heavy deforestation and human development, often found near buildings, town parks, farmlands, and plantations. It is highly arboreal—more so than the eastern green mamba, western green mamba, and significantly more than the black mamba. Jameson’s mamba is very agile.

Like other mambas, it can flatten its neck like a cobra when threatened, and its long body allows it to strike from a considerable distance. It is generally not aggressive and will try to flee if confronted. In Nigeria, males fight each other for access to females during the dry season (December, January, and February). Mating was recorded in September in Kenya’s Kakamega Forest.