Boomslangs are found throughout Zimbabwe and are the only large green snake that is found outside the Honde Valley and a few other areas along the Eastern border. Large green snakes found in the Honde Valley, can be, and usually are, Green Mambas. For some reason boomslangs are not that common in the Zambezi Valley. Only the males are green, the females are brown, olive or grey with an off-white under belly. They are the only snakes in Zimbabwe where the male and females are different colours. The males are a striking green and sometimes the scales are edged in black. The shade of green can vary, even becoming a powder blue in some specimens. The juveniles are a dark mottled grey or brown above, often with markings quite similar to a Vine or Twig Snake. The most distinctive feature in boomslangs, both male and female, is the very big eye. They are comparatively large snakes, sometimes attaining a length of 2m or more. The juveniles only change to green, if they are males, after they reach a length of 750mm or more. This means that any green snake that you encounter that is less than 750mm – 1000mm long and is not in the Honde Valley, or a few other areas along the Eastern Border, will be a non-venomous and therefore harmless snake.
Boomslangs, as their name implies, are mainly tree dwelling snakes, but they are quite often found on the ground searching for prey or moving from one tree to another. They have a fairly catholic diet and will often take frogs and sometimes small rodents, which they have to go down to the ground to search for. However, chameleons, bird’s eggs, fledglings and small birds make up much of their diet. In captivity they readily take frogs (not toads!) and can be enticed into eating mice. They are diurnal snakes.
As a defensive action, they will initially inflate their necks, and then most of their body if they are not left alone. Striking and biting is a last resort, as it is in all snakes. The Boomslang is quite shy and less likely to bite than most other snakes. It is usually only snake handlers and catchers that seem to get bitten, but very seldom. This is not because the Boomslang is back-fanged and has to find a narrow part of the body e.g. a finger, to be able to get its fangs in, which is what most people believe. The fangs are half way back, not right at the back and the snake is able to open its mouth up to 180 degrees, which means, theoretically, that it can get its fangs into a flat surface! If it does bite the snake may inject a very small amount, but extremely potent haemotoxic venom, which prevents the blood from clotting. Without treatment the victim will bleed to death. Specific antivenom is available only from the S.A.I.M.R. Laboratory in Pretoria, South Africa. Positive identification of the snake is essential for a medical doctor to be able to obtain the antivenom. Symptoms are relatively slow acting and victims sometimes appear to be OK initially, but succumb a few days later. Medical observation should be continued for at least three to four days. Bear in mind that even if the fangs have penetrated the skin, it doesn’t mean that evenomation has occurred. The antivenom or serum is very expensive, so make sure you have been bitten! The good news is that, as already mentioned, only handlers and catchers seem to get nailed!
Up to 15, sometimes as many as 25 eggs are laid at the beginning of summer. The eggs hatch 3 to 4 months later. They are generally laid in hollow tree trunks and leaf compost on the ground.