Farmer's Weekly (South Africa)
Don’t forget your snakebite kit: Part 3
In this third article, we continued our series on snakebites with the treatment thereof, as well as the difficulties in identifying snakes in any given area due to the differences in colour within species.
The venom of a spitting cobra in the eyes often causes a “panic situation”, especially when there is no milk available. But that is another fallacy: any clean, harmless liquid can be used to wash the eyes, says Dr Neil Goodwin, head of the intensive care unit at Addington Hospital in Durban, KwaZulu-Natal.
“Wipe the excess venom off the face, away from the eyes, with a damp cloth, and wash the eyes with clean water. The idea is to dilute the venom and clear out any venom remaining on the eyelashes or under the eyelids.
“Repeat if necessary and keep the eyes covered. Incorrect treatment damages the eyes, not the venom.”
Another expert, herpetologist Fritz Muller, director of the snake park in Durban, agrees with Goodwin’s advice.
“The polyvalent antivenom manufactured in this country neutralises the venoms of all of the important Southern African species listed in the package instructions,” he says.
“It isn’t imperative to identify the snake before injecting the serum when signs and symptoms warrant it.”
COLOUR DIFFERENCE
Muller says it is difficult for the farmer to identify positively every species in his or her area because of radical colour differences within species in different localities.
The black mamba (Dendroaspis polylepis), for example, can range in colour from a pale olive-brown to dark brown – it is never black, the name being derived from the black lining of its mouth.
“The process of natural selection ensures that each species blends with its particular environment,” he says.
A pale-coloured puff adder (Bitis arietans) that mates with a dark specimen will produce young ranging in colours between the two extremes.
Predators will, however, prey on snakes that do not merge well into their environments, ensuring the survival of those that best match their surroundings.
This colour difference within the same species applies to many venomous snakes. The rinkhals (Hemachatus haemachatus) is an excellent example, being a uniform black or light brown in Limpopo, and black with orangey-yellow crossbands from Pondoland in the Eastern Cape to the south-western Cape.
LIMITED SENSES
According to Muller, snakes have limited senses. They have no external ears and cannot hear airborne sound, and they have very poor eyesight that can only distinguish moving objects.
They have well-developed senses of smell, using their tongues to pick up particles of scent. By flicking their tongues over objects, they can detect whether they are alive, a function that is vital to their obtaining food.
Snakes are very sensitive to vibrations, which are picked up by the rib and head bones, and because most species are inclined to avoid contact with humans, they try to escape, rather than attack.
“Snakes do not attack humans,” emphasises Muller. “They protect themselves using their speed and agility to avoid anything that poses a threat, and only bite when cornered or very afraid.”
There is one exception, however, and Muller warns that the puff adder, which is particularly slow-moving and lethargic, uses camouflage as its main defence. When approached, it coils up and lies quite still, and then retaliates if stepped on.
KwaZulu-Natal, because of its climate, has the largest snake population in the country, and the highest incidence of poisonous snakes.
CAN BE AVOIDED
Muller says that about 90% of snakebites can be avoided if people wear boots in dangerous areas, since most bites are on feet and ankles.
Being cold-blooded, snakes assume the temperature of their surroundings, with each species having an optimum range of temperature preferences.
For this reason, they can be found in cool, shady spots in hot weather, and warmer places in cool weather.
This article first appeared in the 3 January 1986 issue of Farmer’s Weekly and has been edited to adhere to the current style of the magazine.