Boomslang (Dispholidus typus)

Description

A long slender snake, with an average length of 1.5 meters growing to over 2.0 m in length, with a large blunt head that is distinct from the neck. It has a very large eye, which is characteristic. The body has keeled scales in 19 oblique rows at midbody. The colour is variable, with the females normally grey or brown, and the males green with black edging to the scales giving it a barred effect, or black on the dorsum with a yellow spot on each scale and a yellow belly. The juveniles are grey, with a brown head and white jaw, with the eye bright green. It is often stated that green individuals are males and brown individuals are females, but this is not always the case.

Dentition

The maxilla bone carries from 1 to 3 large grooved fangs on the back of the bone. The fangs are situated below the eye of the snake. It is also often stated that this snake can only deliver a bite on a finger because the fangs are situated in the back of the mouth, but this is not the case. A boomslang can deliver a bite to the arm, leg or shoulder. There is considerable movement in the maxilla bone so the fang can be swung forward and almost 90 degrees to the plane of the mouth, and although the fang is positioned under the eye, the mouth has a very large gap, making it relatively easy for the snake to inflict a bite. However these snakes are reluctant to bite.
Venom

The venom is haemotoxic and causes internal hemorrhage. Clotting factors II and X are attacked by the venom. This removes fibrinogen from the blood causing the blood to go thin, which then results in a bleeding syndrome. Large patches of ecchymosis will indicate bleeding under the skin. The venom is produced in minute quantities of about 1 – 15 mg. This is the most venomous of the African snakes, with an estimated lethal dose for a man is about 1mg.The venom is slow acting, with death occurring from 24 – 72 hours or even longer after a bite was inflicted. Monovalent antivenom is produced in South Africa for this snake’s bite, and is very effective, even days after the bite. Because of the slow acting venom, there would normally be enough time to get to a hospital where proper medical treatment in the form of monovalent Boomslang antivenom is the preferred form of medical treatment. The Boomslang was for many years considered a semi-venomous snake, and thought not to be capable of killing a human. However in 1956 the famous American herpetologist, Karl P. Schmidt of the Chicago Museum of Natural History received a single fang bite from a 75 cm specimen, and died 24 hours after the bite. The deadly nature of this venom was subsequently studied in South Africa and in the early 1960’s the monovalent Boomslang antivenom was developed in South Africa.

Distribution

From the Western Cape along the south coast, along the KZN coast, northwards into Mpumalanga, Gauteng, Limpopo, North West, and Northern Cape. Further north into Mozambique, Botswana, Namibia and north throughout sub-Sahara Africa.
Habitat

The name Boomslang, which is used universally, is Afrikaans for “tree snake”. So from this it can be surmised that the Boomslang is a tree living snake. They prefer savanna and open bush to coastal bush. Also found in very sparsely treed areas, like the Highveld of Gauteng, where it occurs along tree fringed streams and rivers. Although the Boomslang hunts and spends a lot of time in trees it will descend to the ground to cross open gaps between trees and will also go underground when the weather is inclement.

Habits

This snake is active during the day. It avoids human contact and rarely bites, but will demonstrate its displeasure when it is molested by inflating the front part of the body. From this position it may strike out at its aggressor. Because it hunts in trees the warnings of birds will normally alert people to the presence of the snake. The fangs are large, and the gap is considerable, allowing the snake to get its fangs into an aggressor with not too much difficulty, and although venom may not be injected in this instance, as the snake prefers to chew to get the venom into its victim’s flesh, the venom is so potent that just a scratch could cause serious symptoms. These snakes bite very rarely, and most of the recorded bites are on snake catchers. It is a fallacy that this snake can only inflict a bite on a finger, because it is back fanged. Boomslang are attracted to human habitations because of trees and water and also people keeping aviary birds, which this snake is partial to, and often gets killed because of its inability to escape through the mesh of the aviary, once a bird has been swallowed by the snake. Boomslang females produce 12 – 20 eggs during the early summer and the eggs would be laid in a tree hollow or down a rodent burrow where they would hatch about 60 days later. The babies look very different from the adults. They are grey with a very large head and emerald green eye. However they will react like an adult inflating the front part of the body when annoyed. Baby Boomslang are about 20 cm long when they hatch.

Ringkals, Rinkhals (Hemachatus haemachatus)

Description

A small to medium size snake usually 90 cm to 120 cm in length, but can reach 1,5m. The snake is closely related to the true cobras, but differs from the true cobras in having keeled dorsal scales, in producing live young and in the maxilla bone only carrying the fangs. In all other respects in acts like a cobra, being able to rear up and spread a hood. This snake is more robust in build, compared to similar size cobras, and a specimen of 1,2m becomes quite bulky. The colour is usually a light grey when young turning darker and becoming black when about 1 meter in length. In certain parts of it distribution it has a light yellow or orange colour with dark brown or black bands. The ventral part is normally dark brown or black with one to three white bands on the throat. The name ringkals is derived from the Dutch “ring hals” which means ringed neck, because of the white bands on the neck. The scales are keeled and in 17-19 rows at midbody.
Dentition

An elapid snake with fixed front fangs. The fangs are modified with the venom cannel running through the fang and the discharge orifice making a 90 degree bend thus with the exit orifice facing the front, allowing this snake to spray its venom at an attacker’s eyes. The front or top of an attacker is sprayed at. This snake has to rear up in order to spray its venom, unlike spitting cobra which can spray venom from the ground without rearing up. The venom which comes from each fang in a jet is soon broken up into many small drops which make it easy for some of this venom to land in the eyes. Venom spraying is used as defense. Venom in the eyes causes instant burning pain, and the victim will be rubbing the eyes to get rid of the pain. While the victim is thus occupied the snake will be escaping into the grass. The effective range of this venom spraying is in the 2 meter range. Venom in the eyes is not life threatening and no antivenom need to be given. Venom in the eyes is normally a benign condition which will not lead to blindness as long as the eyes are rinsed out with clean water and protected from bacterial infection. Bacterial infection of the eyes could lead to permanent blindness.

Venom

The venom is both cytotoxic and neurotoxic. The effects are not as potent as those of other cobras, and there are few bites to humans as this snake tends to spit rather than bite. The bite presents as a Painful Progressive Swelling syndrome and the local effects of a bite can be quite severe, and the risk of a finger amputation is quite high if a serious bite is sustained on such an extremity. Neurological effects could also manifests and include general paralysis and impairment of breathing, which can lead to death. Estimated lethal dose is 50 – 60 mg and the venom glands have a capacity of 80 – 120 mg, average yield is 100mg. However these snakes do NOT feature in human bites. Dogs get bitten when they attack the snake.

Distribution

Found from the Western Cape along the south coast, northwards into KZN, Free State, and Highveld areas of Mpumalanga, Gauteng, North West and also Limpopo. Further north it is only found in the Inyanga district of Zimbabwe.

Habitat

This snake prefers moist grassland areas that experience cold, frosty winters. It is common on the Highveld, but avoids bushveld areas.

Habits

This snake is active during the day. Starts its day with a period of basking in the sun, usually from about 8 to 9 am, after which it will start moving around in search of prey, which includes frogs, toads, rodents, birds and their eggs, lizards and other snakes. It will raid chicken runs, and is often found near homesteads in search of prey or water. Dogs on the Highveld in the Johannesburg area kill many of these snakes, the dogs normally ending up with red, inflamed eyes from the venom spray of the snake. Occasionally the dogs may end up bitten, and smaller dogs may die before they can be treated by a vet. This snake will usually flee, but if cornered it will face its attacker, rear the front of the body off the ground and spread a broad hood, exposing the black with white bands on the throat. A very impressive sight! From this position it will lung forward and spray its venom at an attacker, the body hitting the ground and at the same time the snake emits a loud hiss. If the threat from an attacker is kept up, the snake may drop to the ground and turn the front of the body over, open the mouth and lay there as if dead. A very effective ploy that has fooled many people as well as dogs to leave it alone. It will later come to life again when there is no threat and move off. This snake should therefore not just be picked up as it may bite if carelessly handled while playing dead.

Reproduction

The Ringkals is a viviparous meaning it is a live bearing snake. The embryos develop inside the oviduct of the female’s body in a clear membrane with no egg shell and develop until they are ready to be born. This can take as long as 5 – 6 months. During the latter half of this gravid period the female does not eat as her bulk makes eating uncomfortable. The female then lays the embryos when they are fully developed usually from late December to late February. As soon as the baby snakes are laid and they see light, they start wiggling and with a sharp egg tooth on the snout break through the clear membrane and move off to find their own place to stay and hunt. They are about 20 cm in length, as thick as a pencil and exact replicas of the a cobra.

Forest cobra (Naja melanoleuca)

Description

This cobra is of medium build, but becomes robust and thick set in specimens over 1,5m. Rears up high and spreads a long narrow hood. The head is distinct from the neck. Large specimens have very broad heads with bulging temporal muscles. This cobra can reach lengths of 2,7 m. Normal length is 1,5 to 1,8m. Any specimen over 1,8 m is an impressive sight. The front part of the body is a light yellowish-brown, to bronze, gradually darkening towards the tail, which is black. The scales are smooth and shiny, in 19 rows at midbody.

Dentition

This large cobra has fixed front fangs. This snake does not spit its venom.

Venom

The venom is a potent neurotoxic/cytotoxic mix with local tissue destruction around the bite area. Venom yield 100 – 300 mg, average 250 mg. Because of this cobra’s size it is a very serious bite that needs immediate medical attention and large amounts of antivenom to neutralize the venom. However these cobras do NOT feature in bites to people even though they are very common in KZN.

Distribution

This is a snake that prefers coastal bush, from Tongaat on the KZN north coast, northwards into Mozambique and also eastern parts of Zimbabwe with a distribution further northwards through Tanzania, Kenya, Angola, Zambia, Malawi, the DRC, and into West Africa.

Habitat

This large cobra prefers low laying coastal bush. As the bush gets drier the snouted cobra replaces it, although the two snakes could be found in the same areas in places like Richard’s Bay and Mtubatuba in KZN Province of South Africa.

Habits

This large cobra normally tries to flee and will also use trees to make good its escape. It climbs well and fast to avoid contact with any potential enemy. It is slow to strike, but if cornered it will rear as high as 80 cm and spread a narrow hood. It can be very common locally. Sometimes active during the day, or on overcast days but main activity is towards the evening, when it forages for suitable prey such as frogs, toads, rodents, snakes and birds and is a raider of chicken runs. Until recently no bites have been recorded by this snake that could positively be ascribed to this cobra. A snake park worker was however bitten in early 2001 and suffered serious neurological symptoms as well as tissue destruction at the bite site, with permanent scarring. Large amounts of antivenom will be required to neutralize the massive amount of venom these snakes are capable of injecting. As with all cobras, these snakes hang on and chew when they bite, and the snake must be forcibly removed. This is a non-spitting cobra.

Berg Adder (Bitis atropos)

Description

This is a small adder that on average grows to 35 – 40 cm in length, with a maximum of 49 cm. The head is covered in small, keeled scales and the head is triangular in shape and distinct from the neck. The eye has a vertical pupil. The common name Berg adder is derived from Afrikaans and mean mountain adder. This should then point to its preferred habitat.

Dentition

This small adder has hinged front fangs.

Venom

The venom is a cytotoxic/neurotoxic combination. Pain and swelling will take place at the bite site. The swelling is normally from the bitten finger to the whole hand but can go to the elbow, or in severe cases go further up the bitten limb to the shoulder or even onto the trunk of the body. The neurotoxin affects cranial nerves and causes dilation of the pupil, droopy eye lids, loss of the ability to focus the eyes, loss of the senses of smell and taste, facial paralysis, and in bites to children can also lead to the paralysis of the diaphragm which could lead to death. No recent deaths recorded for bites from this snake.

Distribution

This snake is found on mountain ranges from the Cape Fold Mountains into the Drakensberg Mountains of Lesotho, KZN, Mpumalanga, and Limpopo Provinces. It is also found in the higher escarpment areas of Swaziland, as well as the eastern highlands of Zimbabwe.

Habitat

This snake prefers high laying areas on mountains.

Habits

This small adder is found in mountainous areas and is active during the day when it will come out of hiding to bask in the sun. It will hide under rocks or in small rodent burrows to escape the winter snows. It feeds on frogs, lizards and rodents. The female gives live birth to 4 and up to 15 young in late summer. The baby snakes are an exact replica of the parents and are about 10 cm in length at birth.

Zebra Spitting Cobra or Barred Spitting Cobra (Naja nigricincta nigricincta)

Description

This is a medium size cobra of 1.2 to 1.5m in length, with smooth scales in 21 rows at midbody. The head is distinct from the neck and the adult colour is light grey to pinkish with about 70 black bands that encircle the body and tail. The common name of zebra spitting cobra is derived from these light and dark bands around the length of the body. The throat has a broad black band which shows prominently when this cobra rears up to face an attacker.

Dentition

This small cobra has fixed front fangs. The hollow cannel that delivers the venom is modified with the discharge orifice facing the front, allowing this snake to spray it venom at an attacker’s eyes. Venom spraying is used as defense and venom in the eyes will cause instant burning pain which gives the snake the opportunity to escape the attacker.

Venom

The venom is cytotoxic causing pain and swelling and superficial skin and subcutaneous damage. Numerous bites from these snakes have been reported with extensive tissue damage the end result. This snake is very similar to the Mozambique spitting cobra in its habits. Victims get bitten while sleeping at night in their inadequate mud huts. The snake will find a person sleeping and bites because the snake thinks it has located food in the form of a warm-blooded prey animal. Namibian doctors claim that the polyvalent antivenom does not neutralize this snake’s venom, but this is not true. The problem is delay in reaching a hospital, and the timeous intravenous injection of antivenom, rather than its efficacy. Tissue destruction starts taking place as soon as the venom is injected, and because of the long distances in Namibia, the victim will probably arrive too late for the antivenom to be of any use.

Distribution

From central Namibia, northwards to southern Angola.

Habitat

Arid savanna bushveld. This is a very common cobra in northern Namibia.

Habits

This spitting cobra is very common in the northern parts of Namibia. As with other cobras its main activity seems to be at night, but they can also found abroad during the day. This snake has the ability to spit its venom, which would be its first line of defense when escape is cut off. This cobra is attracted to human habitations by the presence of rodents and water, and would then come into close contact with people. People get bitten while sleeping on the ground at night and the snake mistakenly biting a person on the ground that it though was prey. This is very serious bite that needs to be treated with polyvalent antivenom ASAP, to limit the tissue destruction. Death is rare in adults but is possible if a child gets bitten. If antivenom is delayed there may be extensive, superficial skin damage that will be removed surgically about a week after the bite. This open wound will then be covered with a skin graph. Unless infection sets in the risk of death is low with this cobra’s bite.

Gaboon Adder (Bitis. gabonica)

Description

A large adder with adults reaching 1,2 – 1,4 meters in length in SA, but this snake grows to 1,8m in East Africa. These large individuals would have fangs up to 50 mm in length. The head is very broad and covered with small keeled scales and distinct from the neck. The tail is very short, especially that of the female. The colour is a mixture of purple, pinks, browns and white or cream. The head is normally creamy white on top and the side of the head has two black triangles, one below the eye and one that runs to the angle of the jaw. There are 10 – 12 rectangular white markings on the back. The sides look like butterfly wings have been pasted onto the snake, being very colourful, and there are half-moon patterns of purple on the sides. The ventral part is a uniform dirty creamy colour with darker blotches. The scales are heavily keeled and in 33-46 rows at midbody.

Dentition

Hinged front fangs normally 20 – 25 mm in 1,2 to 1,4 m individuals, but this species of snake holds the world record for fang length. A very large snake 1,8m in length from Kenya, had fangs of 50mm in length.

Venom

The venom is cytotoxic, neurotoxic and haemotoxic but the effect of a bite is mainly cytotoxic in its action in man, with the normal disfiguring result at the bite area that is associated with this type of venom. The neurotoxin is specific in its interference with heart muscle conductivity and can cause cardiac arrhythmias so it is better known as a cardio toxin that causes atrial arrhythmia; prolonged QT interval and T wave inversion. The haemotoxic venom also inhibits platelet aggregation and converts fibrinogen to fibrin causes a DIC condition and the victim can bleed to death. The LD50 in mice is less that of the puff adder; however the venom yield is 500 – 900 mg of venom, with an average yield is 600mg. The combination of large fangs with large quantity of venom would make for a far more serious bite than that of the puff adder. Collapse within 15 minutes has been recorded after this snake’s bite.

Distribution

This snake is rare in South Africa. It is found from St. Lucia on the KZN coast, north into Mozambique and eastern Zimbabwe. Further north into Zambia, Angola, Zaire, Congo and countries in east, central Africa.

Habitat

Inhabits permanent rain forests that would not be subject to high fluctuations in temperatures from season to season.

Habits

This large adder is potentially very deadly, but has a mild disposition and rarely bites, even when pressed to do so. This is a good thing as a bite is very serious and a medical emergency. Few bites recorded throughout Africa. Most bites have been recorded to snake handlers, with mixed results from mild to very serious. In one case the victim was bitten when he wanted to remove the water dish from the snake’s cage. This was probably a feeding response, and the victim collapsed 15 minutes after the bite. Large amounts of polyvalent antivenom injected intravenously, saved the victim’s life. There was some scarring at the bite site in this case. The main activity is at night, when the snake will emerge from under leaf litter on the forest floor and move off to hunt or find a suitable spot to ambush prey that consists mainly of rodent and ground living birds. In St. Lucia these snakes move from the forest to clearings in the forest that are covered with high grass where its favorite prey, large vlei rats and wood rats are found. Many of these snakes get killed by road traffic when they cross roads. They are also killed on sight by African hunters who will then eat these snakes. The meat is highly favoured by many African hunters.