Colours of Wildlife: Puff Adder, Part I
Created | Updated Dec 7, 2014
Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
This week I proudly bring you one of South Africa's most notorious snakes, the Puff Adder, Bitis arietans. This snake actually occurs through all of sub-Saharan Africa, except for the moist rainforest belt. It inhabits woodland, grassland, savannah and shrubland, only being absent from the driest desert regions and high mountains. There is one disjunct population north of the Sahara in southern Morocco, and it also occurs in the southwestern parts of the Arabian Peninsula. It is perhaps the most common and widespread venomous snake species in Africa. Unfortunately that means that it is also responsible for most snakebite deaths on this continent.
A Powerful Venom
Puff Adders, like many other members of the adder and viper family, have heads markedly broader than their necks. The broadened head of this adder comes from the enormous venom glands it has in its cheeks. Its head also contains its huge fangs. These fangs are hinged, and when its mouth is closed, they fold backwards so as to fit in it and not puncture its lower jaw. When the puff adder strikes, the fangs swivel forward. At the base of the fangs, there is a venom 'sack' that when squeezed squirts out the venom through the hollow fangs, which are much like hypodermic needles.
The venom of the Puff Adder is particularly nasty. About 100 mg (that's to say one tenth of a gram) of it is enough to kill a healthy adult human, and a bite may inject anything from that amount, to 750mg. The venom is cytotoxic, meaning it destroys tissue. This being intended as a fun column, I am not going to describe the effects of the venom in any greater detail. What I will say is that if you're bitten by a puff adder and manage to get prompt and proper medical treatment, your chances are actually quite good. As it is, currently less than a tenth of the people bitten by puff adders die. The key to survival, and to not suffering lasting injury or scarring, is getting to a doctor or hospital quickly, and knowing that it is a puff adder which bit you. Different poisonous snakes in Africa and elsewhere have quite different kinds of venom, and the anti-venom that helps for one, does nothing for another. Therefore it helps to be acquainted with venomous snakes. Here in South Africa, only a few species are dangerous, and they are easily distinguished from each other.
Know your Adder
My illustration and photos give you everything you need for identifying a puff adder. This snake has a remarkably thick body. It is large, often reaching 1 m in length; exceptional individuals reach 1.9 m/6'3" and a weight of 6 kg/13 lbs. As I've said, its head broadens to the rear where it is noticeably wider than its neck. Lastly, the puff adder has markings meant to camouflage it in the bush: a brown body with fairly coarse, visibly keeled scales, marked in alternating lighter and darker bands. The exact shade of brown varies regionally, and some are very boldly marked, but overall the pattern is the same and easy to recognize. The only other similar snake over here is the Gabon Viper, which differs in having a smoother appearance, a comparatively larger, broader head, and in inhabiting more densely wooded and forested country. But the Gabon viper is rarely encountered and at any rate its venom is similar to the puff adder's and similarly treated. There are other venomous adders in South Africa, the most dangerous being the mountain adder, but this snake is much smaller than the puff adder.
A Lazy Snake
There is a town here in South Africa named after the puff adder, in Afrikaans – Pofadder. Douglas Adams himself used this town's name in his 'The Meaning of Liff' books. To the uninitiated: these books use place names for creating new words to describe things for which no words existed previously. Douglas used the name 'pofadder' to mean 'a snake that can't be bothered to bite you'. Well, this is almost true of the real puff adder. This snake is one of the laziest of all, spending the vast majority of its life just lying there. Unfortunately it often chooses to lie in footpaths used by humans or animals. These spots are open and sunny, and puff adders enjoy basking. When something approaches it on the path, it can't be bothered to move away. Instead it inflates its body and makes a low warning hiss, from which it gets its common name. But people who are not very attentive are unlikely to hear this. The puff adder is furthermore so excellently camouflaged that it is not easily seen either. If the person is lucky, he or she will step over the puff adder and never realize how close they were to disaster. But if he or she actually steps on the puff adder, it will at last be stirred from its lethargy and respond by striking. The puff adder's strike is one of the fastest and most powerful of all snakes'. It can strike forward, backward or sideways. Because of the speed and power of its strike, and its long fangs, it can penetrate tough trouser fabric and even leather boots.
The puff adder only strikes at humans in self defense. Because of its lazy nature, it doesn't need much energy and can get by on infrequent feedings (in captivity an adult can do well on one mouse a week). It preys on small vertebrates: birds, amphibians, reptiles and small mammals. It hunts mostly by night. It is an ambush predator: it lies in its spot and waits for something suitable to come by. It can strike as soon as something comes within a distance of about a third of its own body length. It strikes and immediately lets go, waiting for the venom to do its work. If its victim wanders off before dying, the snake can track it through the bush, using its heat detecting sense. It also uses its forked tongue with which it can 'smell'. The trail of its victim will stand out, marking sand, soil, rocks, leaves and grasses in the cool, dark night. Once its prey has succumbed, it will swallow it whole.
Puff adders usually move by 'sailing' straight forward; actually they are using their keeled belly scales to grip the soil and drag them forwards. But they can move faster, if necessary, by undulating their bodies from side to side. They can climb trees and sometimes bask in low bushes. They can even swim!
Females attract mates by releasing a chemical compound called a pheromone into the air. The males detect this with their sensitive smelling tongues, and home in on the females. Several males can compete for the same female, using a ritualized display of neck-wrestling. Like many other adders, puff adders give birth to live young. Actually they do have eggs, but these are maintained inside the body of the female until they hatch. They have the largest litters of live-born young recorded in any snake species, typically up to 50 or 60, but one large female in a Czech zoo gave birth to an incredible 156 baby snakes!
For more about the puff adder, follow this link to Part II of this article.