How would snakes cope with ongoing heavy rains?
Text and photographs Pat McKrill
I’ve never really thought about what would happen to the flora and fauna that are adversely affected during one of those extended periods of excessive rainfall, such as we’ve been experiencing more frequently. What could be the thinking of many creatures on this earth under such circumstances? What are the consequences for them, how would they cope?
Scientists, from Archaeologists to Zoologists, are continually searching for the answers to who came when and via what route, and snakes, although not top of their priority list, have not been ignored. In terms of the 170 or so species we currently have in South Africa, there have not been too many earth shattering new discoveries over the last 100 years or so, so I’m basing my assumptions on what I think might happen to those we’re aware of in the event of an increase in heavy rainfall periods. Although we’ve learnt that over the millennia, some might have evolved from having been aquatic animals, we also know that the bulk of them descended from the lizard family, and of those that continued to evolve, losing such things as legs, arms, ear-openings and eyelids in the process, we ended up with our snake, more of a dry-land dweller rather than amphibian. With that in mind, it would seem that if the excessive rain conditions became more of the norm, the majority of our friends would have to implement some life-changing adaptations, as much as any other similarly affected f&f in the area. Snakes are capable of living for extended periods – sometimes up to months – without food. They’re designed to cope with change.
What would they need to do?
Excluding the mindless killing of snakes on a regular basis by Hom-sap, for a number of understandable reasons from their point of view, snakes are not necessarily permanent residents in a specific dwelling. They might suddenly choose to find another home location should changes demand it, for example, ongoing heavy rainfall in their locality. There could be other physical changes in their environment which could become determinants; (forests being felled, buildings being erected in previously undeveloped areas), changes in staple food availability for numerous reasons – flooding included – changes in the size of the individual, either temporarily, (typically the city-dwelling Night adder Causus rhombeatus after a 3 – toad banquet!) or actual physical growth over time, forcing the occupant to find a new home!
Every snake’s priority. Meal first.
A Herald looking for a bigger door.
A popular suburban B&B
The different groupings.
Let’s look at the 3 loosely categorised snake groupings – the ‘fossorial’ or underground dwellers, followed by the ‘terrestrial’ or mainly above ground workers, and the ‘arboreal’, the tree dwellers and hunters. We can then try to assess as to how each might be affected and consequently expected to cope in terms of any radical or unexpected changes in their essential requirements for habitat, food source and preferred temperature parameters.
The ‘fossorial’ or underground dwellers in the local conservancy areas, are those species that prefer to live and hunt in and around their chosen subterranean or compost-type habitats, spending most of their time in the underground cities (made by the building and burrowing animals – the ants, termites, moles, mole rats etc.) which also become inhabited by many other opportunists.
Anthills are an ideal home for many creatures.
In terms of habitat and temperature control, this is where they’d be grateful to the underground dwelling animals. As we’ve already discussed, snakes don’t build their own homes, so the choice of whether or not to use a ready-made unit is not debatable, and the potentials will have been previously assessed by most of the locally resident snakes – not only the fossorials – for at least two reasons; the proximity/availability of food, and the possibility of a residential option, particularly in the cold winter months and during very hot periods in summer. It’s unlikely that any of the original builders would have built long-term condominiums underground without catering for the possibility of predatorial access or flooding by heavy rains.
A cross-section of an underground dwelling – some so large that they look like huge upside-down leafless trees, the ‘trunk’ at the top (the main entrance) and ‘branches and forks’ spreading out wide and deep below – will reveal the cunning, often deliberately misleading tunnels, alternative entrances and exits, blind tunnels with blocked ends and specifically designed water-protected dwelling pockets within the structures. All of the foregoing merely confirms that we are not the only beings on this planet who have (but possibly seldom utilise) the ability to cater for adversity. In a previous article, we covered the subject of equitable temperatures in these underground ‘cities’ and this factor will remain a drawcard for not only the dedicated fossorials, but other animals as well.*
A Natal Black that escaped the Gillitts gardener’s spade.
Stiletto snakes should adapt as with most fossorials.
Photo: Nick Evans
There will be others, although seldom seen, and not necessarily dark coloured, such as Bibron’s blind snake Typhlops bibronii, the black headed Cape centipede eater Aparallactus capensis and the Common slug eater Duberria lutrix.
Centipede eaters will follow the food.
Not all are commonly encountered because of their chosen hidden habitat which often simultaneously houses their preferred food source. Unfortunately they’re sometimes unearthed and forced to relocate by diligent gardeners, or during building projects, and that which we’re discussing, periods of excessively heavy rains.
In terms of food, most of the animals living underground could experience similar effects upon their food sources in the event of excessive rains, and this might require some dietary fine-tuning on the part of all residents, but unless there’s long-term or permanent flooding, I don’t see this as an insurmountable problem.
The predominantly ground living species, as opposed to the arboreals and fossorials might be the least susceptible to a need for relocation in an excess rainfall situation, where flooding, although distinctly possible in coastal regions, need not be a general threat, and not necessarily as habitat destructive as we’d imagine.
Snakes are among many other animals that do not build any home structure – they’re not equipped to do so, so they’ve adapted successfully to utilising, apart from man-made structures also that which has been available to them over many millions of years.
This Python’s happy with a view from the block.
Perhaps another lesson that we can take from nature is that we can all achieve our goals as long as we remain aware of the resources available around us. The choices are almost limitless, and often, they cost virtually nothing.
Whereas the other two categories are perhaps more habitat specific, the terrestrials have a far bigger choice, ranging from vast open grassland with rocky well-treed outcrops and termite mounds, to thickly covered inland scrub and reed covered wetland areas, down to the coastal cliffs and forests. Because of the altitude differences of these regions, the likelihood of widespread flooding would be limited. Those areas that might flood easily, would possibly be the recognised wetlands, and species commonly found in these areas, for example the green, and brown water snakes, Philothamnus and Lycodonomorphus spp., should not struggle to adapt.
This Brown water snake should readily adapt.
Food sources and temperatures might not vary that dramatically either, so little corrective action should be necessary, apart from a slight move left or right. Riverine dwellers and those who’ve adapted to the areas around man-made dams – the Python (Python natalensis) is a good example – might need to relocate, but again, not dramatically.
Python looking for a new spot.
Dam sites will be prime territory.
The same situation might apply to the bulk of the other terrestrials, most of whom are clinical hunter/killers, for example the striped ones; the sand snakes, bush snakes and the grass snakes. as well as the commonly encountered and well-adapted toad lover, the Mozambique Cobra Naja mossambica.
Grass, bush and sand snakes will find a way, like this Short-snouted Grass snake.
Mozambique Cobra. As long as there are toads.
We can include the ambush specialists – e.g. Puff Adders Bitis arietans who will readily adapt as long as rats and mice are available. None of these species are to my mind, likely to suffer insurmountable damage to their current home environments.
Puffie adapting to our roads.
The downside for our arboreal snakes would probably be the affect the heavy rains could have on their food sources, predominantly the nesting birds. I should imagine that it won’t take the birds long to decide to either redesign their nests, or relocate to more nest-friendly areas – heavier treed, more weather-proof localities etc. This re-location if that’s what it takes, will certainly impact on the better-known tree hunters, particularly Boomslang Dispholidus typus, which often holes up in tree hollows, and the Green Mamba Dendroaspis angusticeps which cleverly pulls in branches and folds the leaves over its body in order to get covered.
Boomslang and birds are joined at the waist.
Fold a few branches over and I’ll be fine.
Those ‘dual-habitat’ species that hunt both on the ground and in the trees, e.g. Black Mamba Dendroaspis polylepis, Vine snake Thelotornis spp. and the specialised Egg eaters Dasypeltis spp. might find the changes easier to cope with.
Vine snakes will join the Boomslang and Green Mamba in house hunting.
Rhombic Egg Eaters will follow the birds.
So will the Southern Brown egg eater…
In terms of coping, we’ve seen that Boomslang are adapting to habitat changes (the loss of trees) quite comfortably, and are seen quite often, doing business in the hedgerows on some of the gated estates as well as in the Macadamia plantations. Unfortunately, I don’t see the Green Mamba adapting as readily to habitat destruction and the relocation of its main food source, and if this situation became the norm, it might put it into the ‘endangered’ category as a result.
Based on what I’ve had the privilege of witnessing in my lifetime, all I can say is that I don’t think man has even begun to fully understand the power of nature and its ability to adapt to adversity and move on.
The SA Weather bureau (18th May 2023) has noted the imminent arrival of another el-Nino period in June – July, forecasting increased temperatures and less rainfall for Southern Africa, but I firmly believe that even if these are destined to be long-term weather changes, the certainly inter-dependent flora and fauna will continue to do what they’ve been doing successfully for millions of years, and I am confident that they will ultimately adapt to the circumstances.
I wait with childish anticipation, to see how they do it.
In a previous article, we covered the subject of equitable temperatures in these underground ‘cities’ and this factor will remain a drawcard for not only the dedicated fossorials, but other animals as well.*
*Built by Animals. (Mike Hansell) Oxford University Press. A must have.
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.
Pat can be contacted at: firstname.lastname@example.org.