vipers & adders - wildlifecampus...wipneus-nagadder habitat: lowveld but marginally extending...

– WildlifeCampus Snakes and Reptiles of the Lowveld Course

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Vipers & Adders © Copyright

Viperidae Hinged Front Fang Snakes This Family is divided into two sub-families. These are Old World and Modern/New World Adders. The predominant factor of this family is they are all venomous, and most are dangerously venomous. Both subfamilies are represented in the course area. All the species are terrestrial but may rarely venture into bushes for basking.

Module # 4 - Component # 9

Vipers & Adders



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Old World Adders - Causinae This group has typical colubrid head scales and the body scales are not keeled. These are primitive adders that are oviparous, smooth scaled and have colubrid head scales. They are nocturnal even though they have the round pupils indicating diurnal habits. The main prey is frogs or toads. The species are relatively small seldom attaining more than 1m in length. There are 6 species throughout Africa but only two occur in Southern Africa, both of which are in the course area. These species also have fixed front fangs as opposed to the typical adder with Hinged Front Fangs, they are the Rhombic/Common Night Adder and Snouted Night Adder.



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Rhombic Night Adder Causus rhombeatus

Characteristics:

Sharpish shaped head Distinct V that is over the head Large easily seen head scales Velvet sheen to the skin Often in damp locations - frog habitats

Other Names: Gewone nagadder, Common Night Adder Habitat: Moist areas within savanna regions Reproduction: Oviparous, having up to 26 eggs



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Description: This species is often confused with the Rhombic Egg Eater. The two quick ways to tell the two apart are that the Night Adder has a more pointed snout and the V-marking is on the head, and not on the neck. Colouration is also different. The ventral scales are usually light cream and may also have a pinkish hue to them. The upper body is normally brown, grey or olive with dark blotches down the body in a rhombic pattern. There are usually between 20 and 30 of these markings.

When encountered they will often hiss and strikeout and will bite. Bites are not serious, but antivenin is effective against this species. No human fatalities have been recorded despite it having large venom yields. They have also been recorded to sham death when continually hassled. Their diet consists almost exclusively of toads and frogs.



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Distribution:

Distribution of the Rhombic Night Adder



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Snouted Night Adder Causus difilippii

Characteristics:

Sharpish shaped head with upturned snout/rostral scale Distinct V that is over the head Large easily seen head scales Velvet sheen to the skin Often in damp locations - frog habitats

Other Names: Wipneus-nagadder Habitat: Lowveld but marginally extending into Highveld savanna Reproduction: Oviparous, having up to 9 eggs



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Description: This species is often confused with the Rhombic Egg Eater and the Common Night Adder. The two quick ways to tell the two apart are that the Night Adder has a more pointed snout and the V-marking is on the head, and not on the neck as with the Rhombic Egg Eater. Colouration is also different. Differentiating the two species of night adder can be done by the shape of the rostral shield. The ventral scales are usually white, but black – grey in juveniles. The upper body is normally brown, grey or olive with dark blotches down the body in a rhombic pattern. There are usually between 20 and 30 of these markings. The Snouted Night Adder is also a lot smaller than the Rhombic Night Adder. When encountered they will often hiss and strikeout and will bite. Bites are not serious, but antivenin is effective against this species. No human fatalities have been recorded despite it having relatively large venom yields. They have also been recorded to sham death when continually hassled. Their diet consists almost exclusively of toads and frogs. Male combat has been recorded but it is a wrestling match, where the submissive or weaker male will move away. Distribution:

Distribution of the Snouted Night Adder



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New World Adders - Viperinae The species in this group have the typical triangular-shaped head, small overlapping head scales and keeled body scales. Their body shape is normally short and stocky. Only three species of this sub-family occur in the course area, of which only one is potentially lethal. All of them have keeled scales, hinged front fangs and cytotoxic venom. The head scales are a series of small overlapping scales as previously described. All of these species are ovoviviparous and hunt via ambush. Most times, they will bite the prey and release so as not to get injured, but if the animal is small, they will hang on to it. The three species examined under this sub-family are:

Berg Adder Horned Adder Puff Adder

Puff Adder



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Berg Adder Bitis atropos

Characteristics:

Short stocky body shape Triangular Shaped Head Puffs loudly when disturbed and strikes out even if the threat is a good distance

away Often on rock ledge basking

Other Names: Bergadder Habitat: Mountainous regions in Mpumalanga Reproduction: Ovoviviparous, having up to 15 young



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Description: An adder that is seldom seen and often inflicts bites on mountain climbers. They bask on rocky ledges and unsuspecting climbers often grab where they cannot see startling or hurting the snake. They are easily excited and will often strike out viciously at the threat and may continue this behaviour for a while after the threat has retreated. Despite the aggression when encountered, they will mostly move away before the threat approaches.

The colouration of this species is quite varied from a grey to grey-olive to a dark brown. A silvery-white line is present from the back of the head to the tip of the tail. Dark triangular saddles come off these lines to the top and down the sides alternating on the two sides. The saddles to the sides below the line are often smaller than the vertebral saddles. The ventral scales vary from a dirty white to a dark grey. There have been some specimens found with very faint marking near to Belfast. The diet consists mainly of lizards, frogs and rodents but will also take small birds and even other snakes. The diet is unusual for Adders in that it is Neurotoxic. This venom seems to target the head, specifically the optical and facial nerves. Often victims complain about drowsiness, loss of taste or sight and dizziness. Antivenin serves no purpose against this venom and most patients are treated symptomatically. Rarely local necrosis at the bite site occurs, but usually, within a few days, the patient will make a full recovery except for the loss of taste where several victims report that this effect persisted for up to a year.



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Distribution:

Distribution of the Berg Adder



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Horned Adder Bitis caudalis

Characteristics:

Single horn-like projection over each eye Short stocky body shape Triangular-shaped head Puffs loudly May submerge most of its' body in loose sand

Other Names: Horingadder or Horingsman Habitat: Arid dry regions in savanna, known to occur in rocky ridges in Gauteng. Reproduction: Ovoviviparous, having up to 15 young Description: It is easily recognizable by its small size but typical adder shape and the two-horned projections above the eyes. Colouration is quite varied from light grey to reddish to olive-grey to light brown. There are a series of dark blotches ventrally and down the sides. Often there is a V-shape to the top of the head, but nowhere near as clear as in the Night Adders. The scales are heavily keeled being typical of African adders in this family. There are rare recorded cases where the horn projections are not present.



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They hunt via ambush, partially burying themselves in loose soil waiting for something to move past. They often take shelter in this manner as well under trees or shrubs. They use their tail as a lure for lizards and gecko’s, causing them to move in close enough for the strike. This snake nearly always holds onto its prey. This is more than likely due to its weak venom, in that the prey will be able to move quite far from where it was bitten.

Male combat has been recorded in this species, but again it is a wrestling match for dominance, seldom if ever causing any harm. When initially encountered they will hiss loudly and quite often recoil ready to strike. They will readily strike out if the threat gets any closer. Bites are not overly common from this species. Generally, intense pain and swelling occurs and some necrosis. There have been no recorded deaths from this species.



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Distribution:

Distribution of the Horned Adder



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Puff Adder Bitis arietans arietans

Characteristics:

Chevron marking to the back Short stocky body shape Triangular-shaped head Puffs loudly when disturbed - Origin of the common name

Other Names: Pofadder, Imbululu Habitat: Most habitats in Southern Africa except true forest and desert. Reproduction: Ovoviviparous, having up to 80 young



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Description: Another very well-known but easily recognisable species. They have very distinctive large triangular heads with Chevron markings that extend down the body. Colouration is varied but in the course region, they are normally brown to grey with dark brown to black chevrons. It is a very heavy-bodied snake that lies in ambush and will lie in paths when basking, often being trodden on by hikers. This is the most prevalent reason for human bites. The camouflage is impeccable adding to the difficulty of spotting the snake. A rare striped phase has been recorded.

It is an easily excitable snake that will hiss or puff loudly when disturbed. Should this warning not be noted, they will recoil, dropping the chin ready to strikeout. They will readily bite, and any bite must be treated as potentially life-threatening. Venom yields are quite large ranging from 100-350mg, and around 100mg is considered fatal. It has one of the fastest strikes in the world of around seven metres per second. Their diet mainly consists of rodents, but they will take frogs, tortoises, birds and even hares.



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Distribution:

Distribution of the Puff Adder

vipers & adders - wildlifecampus...wipneus-nagadder habitat: lowveld but marginally extending...

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