Puff Adder - Bitis arietans
The puff adder is a thick,
heavily built snake has a large, flattened, triangular head and
large nostrils which point vertically upwards. The scales are heavily
keeled, in 29-41 rows at midbody. The body is yellow-brown to light
brown, with black, pale-edged chevrons on the back and bars on the
tail; sometimes the chevrons are lost in the general speckled colouring.
There are dark blotches on the crown of the head and between the
eyes, and two oblique bars from the eye to the lip. The belly is
white or yellow, with a few scattered blotches. Unusual patterns
are known to occur. Males are smaller and more brightly coloured
than females.
This common adder is a sluggish snake.
It emerges at dusk, lying in cover and ambushing prey, which includes
rodents and birds, and even other snakes and tortoises. It has effective
camouflage. If disturbed, it adopts a striking posture and usually
warns by giving a deep, hollow hiss. Once heard, it is not easily
forgotten. It strikes readily. The puff adder normally moves in
"caterpillar" fashion, leaving a straight, deep track
in sand. It may climb into low scrub to bask, particularly when
gravid. It often swims, and lies on warm roads at night. It lives
for up to 14 years if it has plenty of warmth and sunshine. The
venom is cytotoxic, often causing extensive swelling, pain and necrosis.
Yields are large (100-350 mg); 100 mg is fatal in humans. The long
fangs (12-18 mm) inject the venom deeply, and bites are usually
inflicted on the lower leg. Bites are common, but only a small proportion
proves fatal; nonetheless, this snake causes over 60% of serious
bites in the region, and is responsible for most of the fatalities.
Death usually results from kidney failure and other complications
caused by the extensive swelling. It is essential to treat a victim
of its bite for fluid loss, and antivenom should be used in serious
cases. Males engage in combat and trail females in spring.
Large litters, usually consisting of
20-40 young (150-200 mm) are born in late summer. The puff adder
is widely spread throughout Botswana.
|
