Boomslang Snake

The average adult boomslang is 100-160 cm (3¼-5¼ feet) in total length, but some exceed 183 cm (6 feet). The eyes are exceptionally large, and the head has a characteristic egg-like shape. Coloration is very variable. Males are light green with black or blue scale edges, but adult females may be brown.
The head is distinct from the neck. The canthus rostralis is distinct. The pupil of the very large eye is round. The maxillary teeth are small anteriorly, 7 or 8, followed by three very large grooved fangs situated below the eye. The mandibular teeth are subequal. The body is slightly compressed. The dorsal scales are very narrow, oblique, strongly keeled, with apical pits, arranged in 19 or 21 rows. The tail is long, and the subcaudals are paired. Ventrals are 164-201; the anal plate is divided; and the subcaudals are 91-131.

Behavior and diet
Boomslangs are diurnal and largely arboreal. Their diet includes chameleons and other arboreal lizards, frogs, and occasionally small mammals, birds, and eggs from nesting birds, all of which they swallow whole. During cool weather, they will hibernate for moderate periods, often curling up inside the enclosed nests of birds such as weavers.
Venom
Many venomous members of the family Colubridae are harmless to humans because of small venom glands, weak venom, or inefficient fangs. However, the boomslang is a notable exception in that it has a highly potent venom, which it delivers through large fangs that are located in the back of the jaw. Boomslangs open their jaws 90 degrees when biting. The venom of the boomslang is primarily a hemotoxin; it disables the blood clotting process and the victim may well die as a result of internal and external bleeding. Other signs and symptoms include headache, nausea, sleepiness and mental disorders.
Because the venom is slow to act, symptoms may not be manifest until many hours after the bite. On one hand, this provides time for procuring the antivenom, while on the other it may lead victims to underestimate the seriousness of the bite. Snakes of any species may sometimes fail to inject venom when they bite, so after a few hours without any noticeable effects, victims of boomslang bites may believe (wrongly) their injury is not serious.
An adult boomslang has 1.6–8 mg of venom.[8] Various sources give figures ranging from 0.06 - 0.72 mg/kg being sufficient to kill mice in 50% of cases, if the venom reaches a vein (LD50).
In 1957, well-known herpetologist Karl Schmidt died after being bitten by a boomslang. D.S. Chapman states that between 1919 and 1962 there were eight serious human envenomations by boomslangs, two of which were fatal. The South African Vaccine Producers (formerly South African Institute of Medical Research) manufactures a monovalent antivenin for use in boomslang envenomations.
The boomslang is a timid snake, and bites generally occur only when people attempt to handle, catch or kill the animal. The above data suggest boomslangs are unlikely to be a significant source of human fatalities throughout their distribution range.