Variable bush viper, Leaf viper, Hallowell's green tree viper
Atheris squamigera (common names: green bush viper, variable bush viper, leaf viper, Hallowell's green tree viper, and others) is a viper species endemic to west and central Africa. No subspecies are currently recognized. Like all vipers, the species is venomous.
The Green bush viper is a venomous snake found only in Africa. It has a broad and flat head, distinct from the neck which is thickly covered with keeled, imbricate scales. The coloration of this snake is the same in some populations, but variable in others. The dorsal color varies from sage green or light green to green, dark green, bluish, olive, or dark olive-brown. Rare specimens may be found that are yellow, reddish, or slate gray. The scales have light-colored keels and sometimes yellow tips that form a series of 30 or more light crossbands or chevrons. On the tail, there are 10 to 19 chevrons: not always clearly defined, but usually present. The ventral edge of the dorsum has light spots in pairs. An interstitial black color is visible only when the skin is stretched. The belly is yellow or dull to pale olive; it may be uniform in color, or heavily mottled with blackish spots. The throat is sometimes yellow and the tail has a conspicuous ivory white tip. Females of this species are usually larger than males.
Green bush vipers are found in West and Central Africa: Ivory Coast and Ghana, eastward through southern Nigeria to Cameroon, southern Central African Republic, Gabon, Congo, DR Congo, northern Angola, Uganda, Tanzania (Rumanika Game Reserve), western Kenya, and Bioko Island. They inhabit mostly rainforests and prefer relatively low and thick flowering bushes.
Green bush vipers are both terrestrial and arboreal snakes that prefer to spend their time singly. They are nocturnal hunters and their coloring allows them to blend in with their environment and ambush small prey. Green bush vipers are equipped with two front hollow fangs through which they inject their prey with hemotoxic venom making it completely defenseless.
Bites from A. squamigera have resulted in at least one report of severe hematological complications as well as two deaths. Although no specific antivenom is made for the genus Atheris, antivenom for the genus Echis has been shown to be partially effective in neutralizing Atheris venom.
Green bush vipers are carnivores. Their diet consists primarily of small mammals and occasionally birds and small reptiles.
Green bush vipers reproduce once annually, most often during the wet season. They are viviparous, and a single successful pairing can produce up to 19 snakelets, although the average is 7-9. The female carries her young internally during a gestation period of 2 months. Following birth, the snakelets are abandoned by the mother as they are born venomous and entirely self-sufficient. They have a dark, olive coloration with wavy bars, paler olive or yellowish olive with fine dark olive margins, bars at 5 mm (0.20 in) intervals, and a belly that is paler greenish olive. The adult color pattern develops within 3 to 4 months. Females start reproducing at the age of 42 months while males are ready to breed when they are 24 months old.
There are no known threats to the Green bush viper at present.
According to IUCN Red List, the Green bush viper is locally common and widespread 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 remain stable.
