A long, slender, fast-moving snake, with a long narrow, 'coffin-shaped' head, with a fairly pronounced brow ridge and medium-sized eye with a round pupil. The inside of the mouth is bluish-black. Its body is cylindrical, tail long and thin. Maximum size is probably about 3.5 m (unsubstantiated reports of bigger specimens, up to 4.3 m, exist); adults averaging 2.2 to 2.7 m, hatchlings 45 to 60 cm. It is olive, brownish or grey in colour, sometimes khaki or olive-green, but never black as the name suggests. Juveniles are greeny-grey. The scales are smooth and have a distinct purplish bloom in some adult specimens. The belly is cream, ivory or pale green. The back half of the snake is often distinctly speckled with black on the flanks. Some specimens have rows of lighter and darker scales towards the tail, giving the impression of oblique lateral bars of grey and yellow.
Equally at home on the ground, in trees or on rocks, it climbs quickly and gracefully. Very fast moving, it often moves with the head and neck raised high. It is diurnal, but its activity patterns are not well known: in parts of its range it has been described as crepuscular, but in east Africa it is active from a couple of hours after sunrise up to an hour or so before dusk, but may rest during the heat of the day. There are isolated records of night activity. When angry, it can flatten the neck into a narrow but distinct hood, and may also rear up, hiss loudly and open the mouth wide to display the black interior while shaking the head from side to side. Black mambas have been described as aggressive, especially in the 'mating season' but there is little hard evidence of this and no documented cases of black mambas making unprovoked attacks. Most specimens, if approached, move away or freeze, hoping to remain unseen, However, this snake can be truculent if threatened, and rather than retreat may rear up (up to half the body height) and display as described above. A snake doing this is best not approached, for if further molested, they may strike, and due to their great size and agility they can strike a long way out and up. It often has a semi-permanent home, to which it retires in the late afternoon. Favoured spots are termite hills, abandoned antbear and porcupine holes, holes and cracks in hollow trees, rock crevices, old hammerkop nests, beehives hanging in trees and occasionally in roofs!
Occurs widely in low-lying savannahs of southern and eastern Africa. Known from Eritrea and Ethiopia, south to the northern Transvaal and Natal, west to Angola and Namibia, from sea level up to 1800 m, but not recorded from most of Somalia and northern Kenya.
Most common in well-wooded savannah at low altitude, especially with big trees and rocky hills, that provide hiding places for such a big snake. Often found in riverine forest and woodland, but not in true forest. It has also been recorded in semi-desert (Kalahari), coastal thicket and forest (Kenya coast), high savannah (Kenya) and isolated patches of woodland in valleys at the base of plateaux (Ethiopia). Not recorded in grassland or true desert.
Lays from 6 to 17 eggs, measuring approximately 65 x 30 mm. Eats a variety of prey, with mammals recorded including all sorts of mice and rats, bats, squirrels, small hyrax and elephant shrews. It is also known to take birds and other snakes. Legends about the 'crested serpent' or snake with a cockerel's head may refer to black mambas, as big adults occasionally fail to shed the neck skin, giving the appearance of a 'crest'. In the mating season, males indulge in combat, the two males wrestling with bodies intertwined and heads raised up to 1 m above ground, and this has been frequently misidentified as courtship.
Yields of 100-120 mg, LD50 0.28 mg/kg. The estimated lethal dose for humans is 10-15 mg, so a bite from this snake may deliver well over a lethal dose. The venom is both neurotoxic and cardiotoxic, with death often resulting from respiratory failure.
Numerous case histories have been reported, both to snake handlers and lay people. This snake is widespread, large, nervous and willing to bite. Many cases prove fatal and those where symptoms present within an hour of the bite can be expected to be most serious, the usual symptoms being tightening of chest and throat muscles, followed by gradual paralysis of the facial muscles.
Even as late as the 1960s black mamba bites were almost 100 per cent fatal. Now death in unusual for those cases reaching hospital within a few hours of being bitten and receiving vigorous antivenin therapy. However, much antivenin may be needed, and cases where 100 cm3 of antivenin have been used are not unusual. Victims may also require supplemented ventilation. Deaths in rural situations, where victims are delayed in reaching help, are still widespread. It is of great importance that pressure bandaging and immobilisation are carried out on black mamba bite victims who may be even slightly delayed before reaching a hospital with stocks of antivenin, and artificial respiration is most important if breathing begins to fail and a hospital is still reachable.
Homoeopathic name and abbreviation: Dendroaspis polylepis; Dendro-p.
Common names: Black mamba.
Remarks: This snake is found in trees and bushes less often than the other mambas. It is one of the fastest snakes known, and has been clocked at slightly over 7 miles per hour, or perhaps twice as fast as the fastest North American snake. It gives the impression of great speed and in some of the older literature it was reported to "exceed the speed off a running horse". A recent publication estimates the speed at "probably not exceeding 20 mph."
It is certainly one of the most dangerous snakes now living. Although it ordinarily makes for its hole when disturbed, it is ready to fight if suddenly disturbed. The typical attitude of alert defence is with the head raised well off the ground, mouth slightly agape (showing the black lining) and tongue flicking rapidly from side to side. No other mamba shows such peculiarities. When angered, the snake emits a hollow-sounding hiss and spreads its neck. It is said to strike out for 40 percent of its length; the average snake strikes out for 25 to 30 percent.
A large black mamba secretes enough venom to kill 5 to 10 men and few people survive its bite unless antivenin is administered promptly. The venom inhibits breathing and apparently also inhibits the branch of the vagus nerve that controls heartbeat, this causes the heart to beat wildly.
Of two cases where the remedy acted well they both had aversion to marriage and married.
Patients may have flashbacks to old rape experiences; a symptom that came out in the provings and in one of the cases.
Wednesday, March 21, 2012
Black mamba (dendroaspis polylepis)