If you Google “…most snakebite deaths in Africa”, the answer is as follows: The Puff Adder (Bitis arietans) is responsible for more human fatalities than any other snake species in Africa (snake-facts.weebly.com). This is very far from the truth, and one must be very careful when seeking information on Google.
The World Health Organisation reports around 20 000 fatal snakebites a year for Africa, and most of those deaths are because of Carpet Viper (Echis sp) bites in the Sahel district of North Africa.
In South Africa, the 10-12 snakebite deaths every year are largely because of Black Mamba or Cape Cobra bites. The only reason why a snakebite victim dies in the short term, is because the potent neurotoxic venoms affect breathing. Puff Adder venom is potently cytotoxic, causing pain, swelling, large blisters and, in many bites, severe tissue damage that may require surgery. Some victims have limbs amputated.
The venom of this snake is slow in acting and, in severe cases, may result in swelling extending up a limb at a rate of around 10 – 15 cm per hour. After such a bite one has ample time to get to a hospital for proper treatment and fatalities from Puff Adder bites are extremely rare. Small children are mostly at risk.
The fangs of a Puff Adder may exceed 2 cm in length, enabling to snake to deposit its venom deep into muscle where it does most of the damage. From a first aid point of view there is very little that one can do – get the victim to the nearest hospital. Avoid cutting and sucking as well as bandages – an arterial tourniquet will do a great deal of damage after such a bite. One can elevate the affected limb just above the heart to reduce pain.
All bites from Puff Adders are not serious and patients are observed for at least 24 hours to assess the severity of a bite. This involves tracking swelling and analysing blood samples to see how severe a bite is. In serious bites, patients are treated with 6 – 12 vials of Polyvalent antivenom. The cost per vial is just over R2 000 and treating a snakebite is expensive – anything from R100 000 to over R1 million, depending on the severity of the bite.
The Puff Adder is widespread throughout much of Southern Africa but avoids high mountain tops and dense forest. It is a slow-moving snake that spends most of its life well camouflaged. Research has shown that individuals will often live in an area half the size of a tennis court for most of the year, whereas males, in the breeding season, may move several kilometres. This snake is an ambush hunter and will select a suitable ambush site where it may lie in ambush for weeks. If a passing rodent gets close enough the strike is quick – supposedly the fastest striking snake in Africa. Yet half the time the snake misses as rodents are quick to jump and escape. Toads are lured closer by slowly protruding the tongue and wriggling it to mimic an insect or worm.
Professor Graham Alexander and his team at Witwatersrand University did some fascinating research in the Dinokeng Reserve, just north of Pretoria. Several Puff Adders were fitted with radio trackers, and they were followed by students for several years. Some of the students, while tracking individuals, accidentally stood on snakes but were not bitten.
An experiment with gumboots filled with rocks was conducted, and Puff Adders that were well camouflaged were targeted. The gumboot was moved towards the snake like a person approaching on foot, and the snake was then ‘stepped on’. Not a single Puff Adder bit or hissed.
These snakes are perfectly camouflaged and near impossible to see, and it is obviously not in their interest to give away their presence. Further experiments were done with dogs trained to locate snakes, and the dogs could not find the Puff Adders. More experiments followed, using meercat and even elephant, and none of them could find the Puff Adders in camouflage. These snakes, when well camouflaged, are also chemically camouflaged and cannot easily be smelt by predators.
So why do so many people get bitten by this snake? As mentioned, it is a slow-moving snake and is largely active at night. If you accidentally step on one in the dark, the snake will bite.
People often question the usefulness of snakes, and the standard answer is that they are important when it comes to controlling pests like rodents. Just to point out, that there are many predators that control rodents, including predatory birds and small carnivores. The big difference is that these warm-blooded predators eat a near-constant number of prey items every day, and in times of rodent explosions they do not have the ability to double or treble their food intake. Snakes, on the other hand, can survive with 6-30 meals a year (or even less) but in times of abundance they can increase their food intake twentyfold! They can also go down into rodent burrows and consume an entire family.
The Puff Adder gives birth to 20-40 young, each measuring 15-26 cm in length and are perfect replicas of the adults. The record for the most offspring produced by any vertebrate belongs to the Puff Adder – 156 young produced by a female from Kenya in a Czech zoo.
African Snakebite Institute
