What is climate change doing to our snakes?


Are we in the end-game?


Text and photographs Pat McKrill

The Domino effect

The term ‘Domino effect’ was used in the 1950s by American President Eisenhower whilst justifying American involvement in Viet Nam. He was referring to what the Americans saw as a threat to the South East Asian region, describing how neighbouring countries would fall in the event of one of them succumbing to communism. The theory alluded to the fact that if you stood a row of dominoes upright on end and within touching distance of each other, by pushing the first one to fall against the next, the consequential action of that first push, would cause them all to fall, one by one.

I strongly believe that from the day that homo-sapiens learnt to stand upright, he pushed the first domino; the one that started what is now blandly referred to as ‘climate change’.

The first push. 

The part we’re playing in climate change

We have a similar scenario with our environment. We’ve been doing things to the earth and the air around it, that will not only effect the area we’re damaging, but also those areas on the periphery – forever more – across the entire planet. The American depression in the 20’s is a good example of what happens when we try to take control, without factoring in the consequences of our actions.

The Americans were exhorted to go out and multiply, farm, grow food and do all sorts of other exciting things. In the process of preparing the continent for cultivation of crops, huge swathes of land were turned into treeless deserts which eventually changed the climate, and millions of lives in the process. We’re doing a similar thing now, on our own doorstep.

We’re increasingly releasing into our atmosphere, excessive amounts of carbon dioxide and methane gas; we’re allowing seemingly unchecked, rampant deforestation of indigenous species to allow for human habitation, and commercial afforestation with alien species; we’re seemingly ignoring uncontrolled population growth with its incessant demand for land for housing – not food! No matter how small we think our impact might be, what we’re doing, unintentionally or not – along with polluting the atmosphere – is changing biomes, and with those changes will come another bunch of falling dominoes. Specific species elimination is already happening.

Carbon emissions

Methane emissions

Empty web syndrome

The brief I’ve been given for my contribution to this issue, is to offer my opinion as to whether or not there has been an impact on my particular field of interest as a result of climate change. Prior to researching this project, I felt I had most of the answers I’d need, but whilst gathering information outside of my narrow perspective, I soon found out how complacent I’ve been.

There’s no question that climate change is taking place, and I think that some of the other writers might also allude to this knock-on effect in some way or another, and on how their specific field of interest is being negatively impacted upon.

Unfortunately, the terms ‘climate change’ and ‘global warming’ have been put into the same mix, leading to much heated debate, but we can’t ignore the fact that we’re in trouble. The failing health of our environment has a direct relationship with the changes taking place in our climate.

KZN’s sweet green desert = global warming or climate change?

Are we blind to what’s happening?

Over the millennia, there have been – I’d call them evolutionary – adaptations, made by plants and animals to any naturally caused climatic changes as they came along, with the occasional meteorite or volcano that got thrown in now and again. Then along came mankind – a misnomer of note – who decided to rearrange the planet to suit his needs.

Over time, we’ve got used to the changes that have resulted from our self-serving manipulation of the environment, much the same as one would become accustomed to the gradual transformation of the once cuddly puppy, into a humungous man-eating beast. But from what we’ve been hearing and what we’re now seeing, over the last 100 years or so, what we’ve taken to be subtle changes, are considerably less than subtle, they’re now frighteningly obvious. For those who want to get a more wide-ranging, and extremely sobering insight into the subject, I’d heartily recommend the book Scorched, by Leonie Joubert, in which she gives bite-sized scenarios of the effects of climate change upon a vast array of flora and fauna in South Africa.

There is no question that our climate is changing dramatically. I recall from my childhood days further north, the almost predictable seasonal changes by the month of the year, you could count on them. The jerseys came out of the cupboard in mid-June, early July. August was the windy month, and the frogs started calling in September when it always rained. October was always hot, and we couldn’t sit and have candle-lit suppers on the verandah in January – February, without getting bombarded by all manner of insect emerging from the surrounds.

Here in South Africa, anybody over the age of 40 will probably have similar recollections of those almost predictable seasonal changes. Not predictable anymore. Now we can have all four seasons in a week. Some of the frogs that used to become vocal in late August, now start calling in July, and those insect-filled steamy January and February evenings have in most places, become a special event. When it rains – not necessarily heavily – instead of a gentle run-off into the nearby wetland or river catchment, we now have devastating floods – undoubtedly chasing away more than just the snakes in the areas effected.

Insects, what insects? When was the last time you saw a chameleon – once the favourite meal for every boomslang and vine snake in town? It was almost a given. Insects = chameleons = boomslang.

A great deal of the damage done to the environment through what we quaintly refer to as ‘development’, has had devastating consequences for our climate and consequently, our species diversity.

Vine snake


Life in the underworld

I understand that we can’t stop progress, but is what we’re doing really progress? A number of our fossorial (underground) species are undoubtedly being flushed out of their traditional hidey holes, mainly by development and agricultural tillage, something that’s been happening for a long time, becoming all pervasive. The wanton removal of well-rooted groundcover, allows the consequent unhindered passage of rainwater, and the unchecked cultivation of river catchment areas exacerbates the problem.

These seldom encountered subterranean snakes – some of them naturally blind, others with limited vision – play a crucial role in the balance of nature below the earth’s crust, and they’re unlikely to be able to adapt that rapidly to their new, harsher environments, and could be first in the queue to become endangered – if not already being so. Nature’s incredibly adaptive, but the period of time we’re allowing it to perform its adaptations is shortening day by day. Perhaps they’ll manage to adapt in time. But then, as they’re already so secretive, who’s going to know anyway, until it’s too late?

Cape centipede eater

Dominoes. The knock on effect.

Adapt or die?

As humans, we think we’re better equipped to cope with these unpredictable changes, and this is probably why we don’t really factor the devastating long-term effects into our thinking. No food? Hop in the car, off to the supermarket, problem solved. An unusually stinking hot day in winter? No problem, switch on the aircon (no ESKOM jokes please). Perhaps only when we sit and think about it, can we start to understand what animals and plants in the wild can or can’t do, to cope with similar changes. For every living thing on earth, the two staples are food and shelter. Remove those and you’ve got a problem.

I’m not aware of any long-term studies solely on the species statistics of reptiles of the Highway area, so it’s not easy to isolate Highway species from the rest of the country with regard to the effects of climate change, but there’s no question that all our species are being adversely effected.

Snakes are predators. Depending on their species, they eat a range of living animals – eggs are included in my generalisation – and they’re drawn to their food sources, much as birds would be drawn to your garden seed tray, or frogs to your water feature. Once they’ve located a reliable source, there’s no need to move on, and they stick around. Their feeding is not based on casual encounters, they’re pretty fixed on what they’re designed to eat, and what they want to eat, and their survival is determined by such availability – which they actively seek out.

Night adder distribution in Kzn seems pretty well governed by the accessibility of the Guttural toad, although some will stoop to take the occasional Red toad if they’re really hungry. The Mozambique spitting cobra and the Herald are similarly attracted, giving those of us with a resident frog population a clue as to why we might be getting more than our fair share of regular visitations from these three species. In this instance, a similar algorithm might apply as for the boomslang, in this case, insects = frogs = frog eating snakes.

It’s purely by coincidence that insects are the key to the last two chains, but it’s not hard to see how the impact man is having upon the environment can effect considerably more than we first realised, and will have massive repercussions. We cannot fail to hear the sound of the dominoes falling.

Brown Water snake. Frogs, What frogs?

Let’s turn this thing around

Snakes were not designed to be travellers, and because they are not migratory animals in the accepted sense, those we were left with after continental drift had done its bit, remained here to stay. Interest in snakes has really, over the time that man has been on this earth, only appealed to the minority who were mad enough to be interested. The rest of mankind saw them as a curse, and killed them – thankfully that’s changing, albeit slowly.

Because of this almost all-encompassing fear or lack of interest, we have lived with what was relatively limited – now growing – information regarding what species lived where. Consequently, there’s a degree of difficulty in determining down the line, what has disappeared and what hasn’t. When I used to look at distribution maps in some of the reference documents available, I could only think that some of the species reported as being present in certain areas when those documents were published, were either misidentified, or had since died out in those areas.

The pioneering work, Snakes of Southern Africa, written and published in 1962 by Dr. VFM FitzSimons, was revised in 1990 by Don Broadley, and in his preface to the re-printed FitzSimons’ Snakes of Southern Africa, Broadley tells of the early mistakes made in the recording of snake localities, leading to a number of unfounded assumptions on species distribution and consequently, incorrect data was stored as fact. Although a total revision of those records took place later, there are still ghosts walking in the cerebral corridors, making it hard to be accurate about what’s been effected – especially when gathered around a typically South African braai, listening to someone reminiscing about his near death experience, with a Green Mamba whilst fishing up at Albert Falls.

From my narrow snake perspective, the advent of modern technology, a newly vitalised interest in the environment and perhaps a nagging fear of the looming catastrophe, has helped us to get better at recording the correct data, and there are a number of excellent reference books available for the more than casual observer. Despite that availability however, it would be hard for me to say what’s been wiped out or chased away as a result of climate change. But what I’m certain of is that if we carry on as we are, we’ll soon run out of dominoes.

Dominoes. Is this where we’re going?

Author photo: Pat McKrill

About the author

Pat was born in the UK, educated and brought up in Rhodesia/Zimbabwe, and came to South Africa in 1983. He developed an early interest in the study of the behavioural aspects of insects and animals, rather than the deeper scientific side, and he’s worked with snakes for most of his life. Pat conducts educational walks and talks throughout SA and into neighbouring countries where snakes are grossly misunderstood and needlessly killed. He writes articles for a number of publications, and has written the book ‘Getting to Know the Neighbours’, which is all about understanding snake behaviour and is aimed at teaching others how to come to terms with them.

Learn more on his website, Snake Country.