What relevance does the term ‘speed’ have in the life of a snake?


Text and photographs Pat McKrill

The seed of the perception

I’ve been asked to give my input on the theme or concept of ‘speed’, relative to our friend the snake. I should imagine that any followers of my ramblings in these columns, given the same question, will probably have thought a bit about the last time they’d seen or were confronted by a snake, or had heard the term ‘speed’ being used when talking about them.
I don’t know how many times I’ve been told about a snake that ‘shot’ across the path, road, lawn etc. when the speaker was recounting a last encounter with this erroneously maligned predator.

Short Snouted Grass (Whip) snake. Hard to track in the grass.

For me, the term ‘shot’ implies lightning fast movement. It becomes easier to put into perspective if we understand that we seldom see the whole snake. First we might see the head, then all of a sudden we’ll see the mid-body or perhaps the tail, and just as suddenly it’s gone.

Male Boomslang body parts visible in different areas of the tree.

Similar I suppose to our interpretations of length, when for example there’s a large chunk of fear attached to a sudden encounter with 1 metre of nervous Olive House snake that we nearly killed with the lawnmower, and which in our mind (and on our FB post), was a 2 metre black Mamba.

Olive House snake, a reasonable clone of a Black Mamba.

The perception and the reality are seldom the same, particularly when we’re dealing with snakes. Fear is the master of the mind.

Locomotion and snakes

How do snakes move from A to B without arms or legs?

For lineal movement, this long, skin covered, spine and rib-filled tube of flesh and muscle, uses 2 functions linked to its physical make up, that rely upon the surrounds to support their operation. The whole basis of the movements rely upon the ability of the animal to push and pull against any solid objects adjacent to its body. Here’s a very basic overview of the two methods used to achieve the object.

1. Serpentine. A ‘weaving’ motion, assisted by using fixed objects – sand, rocks, clumps of grass, plants etc. – along the way, to provide leverage for the ‘push – pull’ motion. As the snake progresses, it can speed up the movement, whilst using what is termed ‘muscle memory’, to negotiate obstacles in the way in such a way that the full length of the body can follow the same line, without the need to see where the head has been. A snake on your smooth kitchen tiles will battle to move anywhere.

2. Rectilinear. Often used by the Adders, this slow, straight-line movement – almost a crawl akin to that of our Millipedes, is created by various sections of the rib structure, moving back and forth, utilising the wide belly (ventral) scales – louvres – as an aid. Different sections of the body move forward and then stop and pull the rest of the body forward, behind them.

Their ability to hide is deceptive

In a typical scenario where speed is the focus, if you’re ever trying to catch or photograph a snake – you’ll discover that snakes can immediately give the impression of dashing off at high speed in the opposite direction where they’ll hide, probably close to you.

The Spotted Bush snake. Hard to follow in the greenstuff.

A common strategy is where they’ll dash into a potential hiding place, and instead of continuing on their ‘lightning’ fast onward rush to freedom as you would assume, they’ll find somewhere very close by to hide, even as they enter the clump of grass or weeds. They then stop, ‘contract’ body length as much as they can, and remain motionless.

A Mozambique Cobra cleverly contracting itself.

The human (or animal) in pursuit, rushes on in the assumed direction of flight, dashes past the hiding snake centimetres away, and frantically scans the assumed escape trail. The chances of locating the fugitive thereafter, are limited unless you’re following a scent trail.

Terminology is usually determined by historically implanted beliefs, so anything that ‘shot’ from here to there, presumably did so at incredible speed. Don’t get confused here: I’m talking about entire body length (linear) speed of the snake, moving from point A to point B. I’m not talking of the speed of the ultimate strike at the prey, which is a different thing altogether. Any true ‘predatorial’ snake that strikes out slowly in order to secure or envenomate its prey (unless it’s a slug or egg eater) will certainly not die of obesity.

Cultural and embedded beliefs Vs the truth

As we’re on the subject of speed relative to snakes, the one snake in our country, probably in the world, that’s believed to be the leader of the pack when it comes to linear speed, must surely be our Black Mamba. The historical terms ’miles per hour’ and ’feet long’ still pertain, so I’ll stick with them, in the apocryphal tale about the farmer on his horse, being pursued for goodness knows how long across his farm, by a huge open-mouthed and angry 14 foot long Black Mamba, at 40 miles per hour.

Some rationale is required here. Firstly, the snake would be much more inclined to head off in the opposite direction in order to evade the rightly perceived threat of the horse and farmer. Secondly, snakes do not have the capacity to produce the amount of oxygen required to allow them to chase anything anywhere for a prolonged period at an oxygen sapping speed.

I’m repeating myself again, but in my many years of working with snakes in the field, I have never been chased by a snake. Warned with attitude, spat at, or hissed at whilst trying to catch them, yes, but never chased. Maybe I didn’t make them cross enough at the time of the encounter (as we sometimes see in video clips on our phones.) But then I guess, you can get a jellyfish to chase you if you make it angry enough. I doubt that there are too many snakes anywhere else in the world, that differ in this aspect.

Testing the veracity

I know of people who’ve worked with snakes, from layman to scientist, who have taken up the challenge to find out just how fast a Mamba can ‘run’. The most common method seems to have been the one where they take the snake to an area where they can determine a known distance, possibly not less than about 20 metres in any direction from the release point to the furthest point. A rugby field would be about right – not during a game of course.

Any timing device will do, and a wild-caught snake is essential for accuracy, because it would move (away from the release point) a lot faster than a cage-reared snake. At the release point with all systems under control, the snake can be released, and the timing starts. Provided you’ve followed the rules, there should be no need to go and look for the snake afterwards, one ‘run’ should give you the answer you’re looking for. By all accounts, whether in mph or kph, it would seem that they can get up to about 12mph or 20kph in a short burst of speed, if that is required of them. Quicker than most humans can run.

Where speed might be a determinant

Based on historical recounts, it seems there will always be an element of speed inherent in the behaviour of a snake. Except I suppose, when it comes to encounters with Adders, particularly Puff adders, where the word ‘speed’ might not apply to its sprinting abilities, and as most South Africans tell me, “Puff adders are lazy”.

Now this is a great place to switch the focus of the conversation. To make it simple for some of the less informed readers, let’s look at a couple of pertinent facts about the subject. We should all know by now that any wild animal that is deemed to be ‘lazy’, is unlikely to survive for much longer than it takes to read this paragraph. Humans are different, as we all know.

As with all predators, some form of mobility is crucial if they’re to get from point A to point B in their lives, because in order for them to survive, they’ll all need to procure food, and there is no Uber service for wild animals. But even if it’s to do so moving at what we’d term ‘snail’s pace’, it still needs full awareness of all that’s going on around it. A Slug eater is not going to have to run to catch a snail in your cabbage patch, nor is our seldom seen Vine Snake/ Twig Snake/ Bird Snake required to have Olympic skills in order to locate and extract a perceptively frozen chameleon from its hiding spot in the branches.

Vine Snakes eat Chameleons. No need for speed.

Chameleon. Speedy tongue. Vine Snake bait.

They’ll do the necessary, at the speed required at the time, but these hunters will always be aware of the dangers within their surroundings. As is the norm in nature, they too, are likely to be subject to predation themselves by other predators, so a dash of speed now and again will do no harm.

Now what about the Puff adder, or for that matter, any other ‘ambush’ feeder, for that’s what the Puff adder is.

Puff Adder ‘spring’ loaded strike pose.

Non-venomous snakes can also be ambush specialists – our Python is a prime example. To procure a meal, these animals must rely totally upon their ability to remain unobtrusive when in their ambush mode and in the kill zone. Which explains why we can often unknowingly step over or next to, ambushing snakes, which although well aware of our presence, don’t move, presumably in the hope that we won’t step on them. In most situations, they will have pre-determined that we don’t meet their simple prey parameters of size, smell and shape. In their natural habitat, I’d guess that snakes are very specific in their dietary requirements, and seldom will they attempt to lash out in all directions in order to procure any moving object without carrying out the necessary due diligence beforehand. A defensive bite or strike would usually be precipitated by unusual behaviour or aggression by the one who’s bitten. Snakes are not lazy or stupid, they’re very clever, and they won’t spend all week in the zone striking out and missing everything that passes by. The strike speed we refer to in this case, would be that which applies when they reach out to bite (strike), immobilise or envenomate their target. No snake would strike slowly when feeding. They strike very quickly for the obvious reason. And at this point I’ll include standing on the snake, as a good reason for it to strike speedily. This can often be a ‘dry’ bite, designed to warn you rather than kill you – as discussed in previous columns, venom is currency, that doesn’t get willingly wasted.

Tiger snake strike pose.

Herald strike pose.

An aside on the Puff adder strike, and that of similar species (mostly adders) who envenomate and release: they strike out, envenomate as the fangs penetrate, and withdraw immediately – in what could literally be termed ‘a flash’ because of the speed at which it takes place. They seldom hold onto their prey. They will thereafter follow up on the prey, knowing that it will not have travelled far before the venom takes effect. Lazy?? Clinical is the word we’re looking for.

Maximum utilisation of available resources

When it applies in the ‘killing zone’, ambush feeders and foragers alike, venomous or not, would have to procure or envenomate their prey, using their mouths, as quickly as possible, before the prey escapes. This is done by striking out rapidly and, if necessary, holding their prey with their jaws, some of which are deliberately equipped with very sharp, recurved teeth, designed to capture and secure their prey, not chew it.

You might not need linear speed if you’ve got these.

As a relevant aside, I need to debunk the commonly held fallacy that the Python catches its victims with its tail. Not so. Despite the numerous faithfully repeated cultural beliefs one hears, or the gobsmacking – “I was there” – social media recounts, no snake captures its prey with its tail. They have to do so with their mouths, and the term ‘strike speed’ applies. After the capture, the snake would then need to immobilise as much of the body of its prey as possible, in order to avoid it escaping by fighting its way out of the jaws. This would be done normally with constriction, using the rest of the body – comprised of anything from 200 to 300 pairs or more, of strong, muscularly controlled individually operated ribs – to carry out the immobilisation or killing process, which needs to be clinical and rapid, before the snake runs out of energy.

Non-venomous Brown House snake killing prey before swallowing.

Some of the fossorial snakes – Mole snakes or Natal Blacks for example – perhaps because of a possibly restrictive situation at the time, might need to use just their specifically adapted neck muscles in this final constriction phase. As nothing is done at half pace, speed and efficiency is of the essence. Any snake swallowing a still living prey is tempting fate, evidenced by the damage that can be caused to a venomous snake that had swallowed an animal that had not yet been fully immobilised by venom or physical constriction.

Back to the question: Speed is a factor, yes, but it’s just one of the many necessary purpose adapted components required by a healthy snake.

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.

Pat can be contacted at: herpet@snakecountrycc.co.za.