Anthea Johnstone looks at why snakes are feared and how to co-exist with these ecologically important reptiles.
Talking about snakebites and your dog in the same breath makes most of us dog owners feel distinctly uneasy. You know it happens, but you just hope it never happens to you. Recently, while walking on Slangkop mountain in the southern Cape Peninsula, I had the frightening experience of watching my Corgi-cross get bitten on the shoulder by a large Puff Adder. Happily, my feisty little dog made a full recovery – but it could have ended very differently.Most South Africans have frequent access to the outdoors, and we generally like to take our dogs along with us whenever we can. While Africa is still rich in wildlife, that does include snakes. A little knowledge can reduce the likelihood of your dog (or you) being bitten by a snake, and improve the chances of recovery if bitten.
Bone up on local venomous snakes
Only about 10% of snakes in SA are venomous and importantly, a bite from a venomous snake is treated differently from that of a non-venomous snake. “In fact,” says Dr Clarke of Glencairn Veterinary Clinic in the Western Cape, “true anti-venin (sometimes referred to as anti-venom) isn’t only expensive,
it can also be dangerous. There is a
risk of anaphylaxis – an allergic reaction that can be fatal – so we don’t
want to give anti-venin for non-
venomous bites.”Consult field guides, the internet or go on a snake identification course, but find out about the potentially dangerous snakes in your part of the country and learn to identify them accurately.
Don’t go looking for trouble…
Most snakes will attempt to avoid you and your dog, but dogs can be surprisingly keen to get stuck into a snake if they spot it. (Most dogs are bitten on the head, neck or shoulders – which suggests that they weren’t trying to run away at the time). Some familiarity with the habits of snakes will help you stay out of their way.
You
• Choose open paths and stick to them – off-trail hiking can stir up snakes. Be alert and look ahead along the path. Puff Adders are responsible for the majority of snake bites in SA, mostly because they enjoy basking on warm paths and rely on camouflage for protection – so they don’t move away when something approaches.
• Exercise greater caution during summer. Shaun Bodington who runs Imhoff Snake Park in Cape Town and provides a snake rescue and removal service, explains, “Snakes are very active at the beginning of summer. They need to fatten up after a long winter of fasting and they need to find a mate.” He says that another period of high activity occurs two to three months later when juvenile snakes are born and disperse to establish their own niche in the ecosystem. “In my experience,” says Shaun, “snake-bite incidents are reduced by at least 95% during winter.”
• Many snake species hunt at night, so don’t tramp about after sundown without shoes and a flashlight. Snakes are particularly active on well-lit summer nights, especially during full moon when food is available and detectable.
Your dog
• Socialise and train your dog so he is used to obeying you in unfamiliar situations that may startle or frighten him.
• Keep your dog on a lead to prevent him from pursuing high-risk activities like sniffing enthusiastically around rocky outcrops, bouncing through patches of long grass, digging in holes or excavating under logs. This will also protect the local fauna (including snakes), which your dog may harass or even kill if he gets a chance. Habitat loss caused by urbanisation and development is placing massive pressure on wildlife. Don’t let your pet add to the challenges faced by our beleaguered wildlife.
• Snakes are fascinating creatures but don’t allow your dog to investigate a snake that appears to be dead, as many snakes sham death. They don’t always react immediately to provocation, so that ‘dead’ Puff Adder might strike to defend itself – at the mind-boggling speed of 1/26 of a second.
How should you react to a snake?
From his many years of providing a snake removal service to the local community Shaun advises, “Although a snake encounter could be as terrifying for you as it is for your canine friend, try to remain calm and non-confrontational. Snakes are not unresponsive, evil demons – leave them alone and you will be fine.” The bottom line? If you are out in a wilderness area, give the snake some room and let it move off in its own time.
If you encounter a snake on your property, remove children and pets from the snake’s proximity. Without getting too close, try not to lose sight of the snake – and call your local wildlife removal service.
Don’t try to kill the snake or allow your dog to attempt the task – you will be putting yourself and your dog at serious risk. “A snake’s first line of defence is to retreat or remain undetected,” explains Shaun. “Thereafter, it will issue a series of warning gestures, such as hissing, spreading of the hood and mock strikes. However, if this fails or if it is challenged directly, it has no option but to bite.”
Venomous snakes by area Bear in mind that a venomous snake isn’t necessarily a particularly dangerous one. The size of a species’ range, its behaviour and whether it is endemic all determine its potential threat to dogs (and people). For example, in the Western Cape the Boomslang population is quite large, but its distribution is limited and the species is predominantly arboreal (tree-dwelling), so incidents involving a Boomslang and a domestic animal are extremely rare.
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| Snake | Area/s |
| Black mamba (Dendroaspis polylepis) | NW, LP, MP, KZN (northern) |
| Black spitting cobra (Naja nigricollis woodi) | NC, WC |
| Boomslang (Dispholidus typus) | WC, EC, MP, NP, GP, FS, KZN, NW |
| Cape cobra (Naja nivea) | EC, FS, GP, KZN, NC, NW,WC |
| Coral snake (Aspidelaps lubricus) | NC, WC, EC (northern) |
| Gaboon adder (Bitis gabonica) | KZN (northern) |
| Green mamba (Dendroaspis angusticeps) | KZN, EC (northern) |
| Mozambique spitting cobra (Naja mossambica) | NW, LP, MP, KZN (northern) |
| Puff adder (Bitis arietans) | Throughout South Africa |
| Rinkhals (Hemachatus haemachatus) | WC, EC, FS, KZN, NW, GP, KZN (southern) |
| Snouted cobra (Naja annulifera) | NW, LP, GP, MP, KZN (northern) |
The ‘Big 6’: How to identify some of SA’s most dangerous snakes • Boomslang – a placid, but extremely venomous tree-dwelling snake with very large eyes. Colouration is highly variable, from light brown to black, and even bright green. • Puff Adder – a belligerent snake whose colour pattern varies geographically. It may be light yellow, brown or orange with bright or dull chevron markings. • Black Mamba – so named due to the inside of its mouth being black, this aggressive and highly venomous snake is grey to olive-brown. • Cape Cobra – one of the world’s most toxic cobras, the Cape Cobra’s colouration varies from a beautiful gold, through to brown and even black, sometimes with speckling. • Mozambique Spitting Cobra – this snake may be grey, olive or brown, with black-edged scales. Its underside is yellowish or pinkish, with black bars across the neck. It is second only to the Black Mamba in venomousness. • Snouted Cobra (previously known as the Egyptian cobra) – less venomous than the Cape Cobra, but far more deadly due to the larger amount of venom it injects. Its colouration varies from a slightly golden or slatey brown, to dark brown or black with dull yellow bars. |
Snake bites dog – now what do you do?
The dark day has dawned – your dog has been bitten. What now? Without endangering yourself try to identify the snake and if practical use a cellphone to take a photograph of it. Walk the dog slowly back to your vehicle or carry him (to slow the spread of the venom), but be careful. Snakebites are extremely painful and even a gentle dog may bite when in considerable pain.Ignore all the backwoods dogma about first aid for snakebites (such as applying tourniquets and cutting wounds to suck out the poison) as these interventions have limited benefit, if any. Use every moment you have to get your dog proper veterinary attention. Snake venom acts immediately on the body, so quick action on your part will increase your dog’s chances of survival.
Sadly, owners occasionally come home to a dead dog (often accompanied by a dead snake) so you may not be around when your dog is bitten. Typical symptoms of snakebite are puncture wounds (with or without bleeding), a painful area around the bite and breathing difficulties.
How serious is it?
Although a bite from a venomous snake is undoubtedly a medical emergency, snakebites do vary in severity. Some determining factors are the toxicity of the venom, the amount injected (many bites are almost dry, meaning that very little venom was injected), how swiftly the bite is treated and the size of the dog. (Smaller dogs are more seriously affected because the amount of venom injected per kilogramme of body weight is larger.)
The toxicity of the venom determines the speed of its action and the effect it has on the dog’s body. Dr Dukas, also of Glencairn Veterinary Clinic, explains that cytotoxins cause tissue damage and death of tissue at the site of the bite, which can extend to the surrounding area (Puff Adder).
Haemotoxins cause blood clotting problems so the dog may start bleeding internally and lose blood from all sites in the body – lungs, gut, kidneys, gums, eyes, etc. (Boomslang). Neurotoxins act on the nervous system causing respiratory failure, brain damage and loss of muscle use – including the heart muscle (Black Mamba).“In our experience,” says Dr Dukas, “a Cobra bite is the most life-threatening to a dog. The venom causes rapid respiratory depression and death can result very quickly. Large volumes of anti-venin are required and the dog may need ventilators to maintain breathing while the anti-venin is working.”
Treatment, recovery and costs
Because so many factors influence the seriousness of a bite, there is no typical treatment or recovery process. Dr Clarke says, “We had one dog here last year that had to have ten vials of anti-venin – at about R1000 each. Some dogs need to be ventilated at specialist 24-hour clinics, which can be very expensive. Certain wounds from cytotoxic bites require reconstructive surgery to repair the damage. Shock treatment and in some cases blood transfusions can also be required.”Snakebites can have long-term health effects. The muscle loss and associated tissue destruction can be permanent, renal (kidney) failure can occur, and immune system disease can be a side effect of the anti-venin.
The cost of snakebite treatment is highly variable, as Dr Clarke explains. “It may cost the owner R5 or R25 000. Unfortunately, owners need to be prepared to spend large sums of money – with no guarantee of success.”If you live in an area where venomous snakes are common or you pursue ‘high-risk’ activities, you may wish to consider investing in pet medical insurance.
The importance of snakes
Snakes play an essential role in maintaining the delicate balance required for a healthy ecosystem. They are in fact so important that their success or otherwise can make or break an ecosystem. They are a source of food for predators higher up the food chain, and they ensure that their own prey species (such as rodents) don’t become too numerous.
Fast facts • One of the oldest forms of vaccinology is acquiring immunity to snake venom. It was practised as early as AD 60 by the Psylli, a North African tribe. • In Trinidad hunters claim to treat their hunting dogs successfully for snakebite using tinctures made from a number of different plants, insects and caterpillars. • All snakes native to Australia are venomous. • The Cerastes Viper of the Sahara is said to be able to strike the full length of its body and beyond, and has developed a type of launch and jump characteristic to its strike. • The largest snake ever discovered is Titanoboa cerrejonensis, which lived about 60 million years ago. It weighed a hefty 1.1 tons and grew to around 15m. • Recent research has shown that snake venom and its components may potentially play a role in the fight against many bacteria and viruses. • Africa’s very own Black Mamba is the second-largest venomous snake in the world (up to 4.5m). Its potent, fast-acting venom makes it one of the world’s deadliest snakes. What’s more, it can ‘sprint’ to safety at around 20km/hour when threatened. • Even today, snakes are revered in the mythology of many cultures, particularly as a deity who takes the form of a very large snake (called a nāja). In Africa, a snake is believed to be the incarnation of deceased relatives. |
Links:
http://www.imhofffarm.co.za/index.php?option=com_content
http://www.africanreptiles-venom.co.za
http://www.snakes-uncovered.com
http://www.capesnakes.org.za.index.php?option=com_content&task=view&id=3&Itemid=8
http://www.africanreptiles-venom.co.za/snake_courses_snake_handling_c.html