Tuesday, April 5, 2011

More snakes and adders

The one thing that most people know about mongooses is that they kill and eat snakes.
This is like knowing that humans eat lasagne.

Of course, there are snakes and there are snakes.
Big snakes are only too happy to kill and eat little mongooses.
And my dwarf mongooses are the teeniest mongooses there are.
Being rat-sized and the weight of half a can of baked beans, they're ideal snack snake food.
But ONLY if they're caught unawares.

The spotted bush snake (Philothamnus semivariegatus) is about the largest snake my dwarfs can kill. It's a slick, zippy snake, about 1 m (3 ft) long and the thickness of my thumb. Sadly, only the group's oldest members can feast on the spoils because no one else's teeth are hefty enough to pierce the skin.

When walking in the bush alone I rarely see a snake.
But 'see' is the critical word here. Add 15 mobile snake-detectors and it's a whole different story. Last Sunday I spent an hour pottering along with Ecthelion. In that time we met two large puff adders and a Mozambique spitting cobra.

When a mongoose meets a life-threatening snake, it hollers for the group using a special, high-pitched 'snake' call. Everyone immediately comes running. It's a moment I dread. All the mongooses cluster around the snake, flattening themselves down on their tummies, calling and spitting. The snake coils into the smallest possible bundle and assumes strike position. I bite my nails.
At this point, puff adders demonstrate why they're so named. They produce a loud, ominous noise: a deep whooshing hiss like a deflating football, which lasts around 3 seconds and is then repeated over and over. The mongooses are not deterred. Individually they try to dart in and nip the snake's body, leaping backward as it lunges for them. Some even cartwheel half a metre into the air to evade the striking snake. I stand well back, wincing and squirming, with my eyes screwed half shut.

This is an action shot. Unfortunately it features two cryptic species. Can you spot the puff adder (lower centre) and two mongooses (upper right and upper left beneath the grass tussock)?

From my (wimpy) perspective, snake-mobbing is worst when - as now - the group has small pups. I've seen a puff adder (undetected by me or the group) snatch a mongoose pup almost at my feet. It's not an experience I wish to repeat.

But snake-baiting appears to be a learned behaviour in mongooses and the pups are totally clueless. On Sunday, Ecthelion's three smallest members came trotting over to see what all the fuss was about, wending in and out of the mobbing adults and blithely ignoring the huge puff adder poised inches above them. I actually stopped breathing when Hiccup marched right over the adder's coils. But no one else even noticed. The snake and the mobbing mongooses were focussed exclusively on one another; neither could afford a moment's distraction in the deadly exchange of bite and counter bite.

This whole awful scenario ends after about five minutes, when the mongooses lose interest and wander away. I know this is sounds like an anticlimax, but once the mongooses know the snake's presence, and the snake knows it has a whole group to contend with, the peril is over.

A puff adder (Bitis arietans) feeling put upon. Snakes breathe by moving their ribs (called a costal pump) and a puff adder uses the ribs along its entire trunk to 'puff'. Both the inhalation and exhalation are disturbingly loud (75 decibels - the same volume as a vacuum cleaner at 1 m/yard).

Puff adders are the sluggards of the snake world. During the day they lie about cryptically in thickets or rocks, and at night they lie about cryptically on pathways waiting for edible things to stumble into them. Of course this indolent lifestyle has its consequences: although they only grow to about 1.2 m (4 ft) in length, they get embarrassingly rotund, weighing up to 7 kg (15 lbs). If given unlimited food in captivity, they'll literally eat themselves to death.

Puff adders are responsible for more than 60% of serious snake bites in southern Africa. Their long fangs (12-18mm/0.5-0.7") are capable of penetrating soft leather and they inject a potent cytotoxin that causes severe swelling, pain and necrosis. Around 10% of untreated bites prove fatal (due to kidney failure or complications from the swelling) but loss of an appendage is much more common.

Despite the puff adder's reputation, this is the snake I've grown to feel most warmly towards. Why would someone who's snake-phobic feel warmly toward any legless beast? Gratitude, pure and simple.

You see, in my experience, puff adders behave with exemplary restraint. Once, when I was crawling about a termite mound, neatly piling up mongoose droppings (so I could tell if anyone subsequently visited the latrine), I suddenly realised that my scrabbling fingers were only 2" away from the nose of a very large puff adder. It lay perfectly still but its golden eyes were watching me intently. I'm not sure how it felt when a look of horrified recognition passed over my features, but it maintained its perfect immobility.

In a more testing situation, once (while walking the dogs) I glanced down to see a puff adder right beneath my feet. The snake's thickened body was coiled up beside the track, but its head and neck lay out across the path (presumably in wait for passing rodents). I'd actually passed over the snake before I saw it, but not so my dog, who was following along behind me. With horror, I watched as she lowered her hind paw directly down on to the snake's head. But to my amazement, at the very last moment, the adder flicked its head sideways, out of her way, and the dog marched on, quite oblivious. I think I lost a few years off my life, but I can't help but feel profound gratitude that it did not strike.

A coat of many colours. During spring, male puff adders trail females (who waft an alluring pheromone) and neck wrestle each other to win their regard. Mothers bear 20-40 mini adders in late summer.


  1. Very interesting. I had the impression the mongoose was a natural born snake killer. (Thanks to Rudard Kipling and Kim). Grin. ATB!

  2. Phew I am glad the pups managed to survive that meeting. We had many puff adders around when we lived at Raffingora in Zimbabawe but other that one visiting us in the house they really did not cause a major problem. I have a great deal of respect for them though!! Diane

  3. Once after fires on Table Mountain, we had a boomslang in the garden. I know, because our cat produced a miaouw I have never heard since. 'Come here quick, snake snake snake!' And that snake was as thick as my arm, and a lovely green. So long as it stayed over there, in the tree, watching me back.

  4. Next trip to Africa, I'll have to follow mongooses if I hope to find any snakes. Your Puff Adder stories remind me of so many experiences I've had stepping over rattlesnakes before noticing them.

  5. My goodness, puff adders are chunky-looking snakes! Is any type of mongoose big enough to win an encounter with one?

  6. OMG, your posts give my cardiovascular system such a workout. TENSION! Can't imagine seeing the furry adorables battling this deadly behemoth. That's amazing re: how restrained they are--I totally get your appreciation. Very, very cool. Would that I were so non-plussed. And THANK you for the close shot of the snake scale pattern. Heaven.

    P.S. Snakes are the only species where I saw them through a bush, say, then bring up my camera, look through my camera and can't see them, look with my eyes again, find it again, pull up camera, look through view finder, cannot see it, etc. SO CRYPTIC they disappear right before your very eyes. =) bizarre.

  7. Rusty,
    They would if they could; legs too short, snakes too big.

    I've never had a puff adder in the house - hope it stays that way!

    Elephant's Eye,
    Your watch-cat sounds invaluable.
    I've only really encountered a boomslang once. While out in the field, I sat down in the shade of a small shrub. Suddenly all the mongooses came rushing over and started mobbing me. It took a few moments to realise that they weren't attacking me, but were responding to the juvenile boomslang looped in the foliage just above my head!

    Following mongooses is the path to enlightenment (as well as snakes).
    I'm glad you've been able to evade those rattlesnake fangs.

    One of the behemoths of the mongoose world - the Egyptian mongoose (Herpestes ichneumon) - eats puff adders for breakfast (and probably other meals too).
    Egyptian mongooses (marauding throughout Africa, southern Europe and the Middle East) are more than a metre long and weigh up to 4kg (16x the size of my little guys). In the Western Cape of South Africa, 2% of their scats contain bits of murdered puff adder. Of course 2.5% contain munched land snails (thought you'd like to know) so perhaps they aren't so hard-arsed.

    I always find snake-mobbing nerve-wracking, even though they do it so often and I've never seen anyone (other than the snake) get bitten.
    I know what you mean about the view finder thing, although this happens to me with mongooses too!


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