Wildlife | Feb 2020

Boomslang – predator and prey

Barry Peiser

Boomslang (tree snake), like the one in the image, and cobras are regularly sighted at Tswalu winding their way through the massive nests of sociable weavers. These magnificent structures consist of various chambers occupied by mating pairs and their chicks and are usually built around sturdy acacia trees. The snakes move from chamber to chamber looking for food then wedge their bodies into the chamber hole when they find the chicks or eggs they’re after. Then they gorge themselves. Afterwards they often rest for a while on top of the nest or move on to search for more food.

The boomslang is identified by its exceptionally large eyes and egg-shaped head. The dimorphism is colour in this species and the boomslang in the picture is male. Males have a variety of colour shades from solid bright green to rust-red or a combination of black and yellow. Females are a dull olive-brown or grey colour. Hatchlings and juveniles are grey with a massive emerald green eye but change to the adult colours at around 1 metre.

It is mostly arboreal, spending a lot of its time in trees, and diurnal, meaning it is active during the day. It feeds on birds, nestlings, frogs, lizards and occasionally small mammals.

The boomslang is a highly venomous snake and is back-fanged – it has fangs located in the back of its mouth which makes it difficult for the snake to bite humans, other than on a finger. Its venom is haemotoxic which affects the blood-clotting function of the victim, causing internal and external bleeding.

As a relatively small snake, the boomslang faces numerous predators including large birds such as falcons, kestrels, eagles and vultures, as well as other snakes. Some small birds may also mob the snake if they feel threatened by it.