Sunday, October 24, 2010

Uninvited house guests

Last Wednesday was an evening for unexpected visitors.

And unwelcome ones.

I was alerted to my first caller by the dogs. I could tell that they weren't just indulging in their usual nightly spat with the porcupine: they sounded threatened.

Dashing outside, to drag them away from whoever might be about to do them in, I wondered whether I'd run headlong into a leopard (they're forever leaving their paw prints round about). But what I discovered was the back half of a very large African rock python (Python sebae) disappearing into my outside bathroom. The dogs were too afraid to attack (ahh, thank goodness for the salutary effects of an eyeful of cobra venom), but were creeping after it, hackles raised and necks outstretched. Wobbly Cat was standing nearby looking like a feather duster who'd suffered electric shock therapy.

The python, hissing stridently (I've never heard a snake actually hiss before), slithered in among the boxes and paraphernalia I store in this unused bathroom, before wrapping itself around the sink plumbing. At around 2.5 - 3 metres (7-9 ft), it wasn't as big as the one that plagued us last summer, but it'd still see my cats as nothing more than appetite-piquing hors d'oeuvres.

I quickly bundled the pets into the house, to prevent any mishaps, and left the snake to entertain itself amongst my worldly goods.

I'd no sooner got all the animals safely shut in the house, than I turned round to see Wobbly staring transfixed at something under the dining table.

Oh God, another snake!

After a scuffle, I managed to drag, shove or carry everyone (except the snake) into my bedroom and squeeze shut the door. Step one complete. I then fetched my tried-and-true snake removal equipment: the kitchen broom and a poster mailing tube.

Well, at least this one was small. In fact, it was only around 0.5 metres (1.5 ft) long, strangely two-toned (glistening black above and white below) and entirely new to me. With great presence of mind (something I tend to relinquish in the presence of snakes), I snapped a couple of blurry photos as it coiled and uncoiled nervously on the concrete floor. Actually, it looked pretty innocuous; after all, it wasn't hissing or puffing, spitting or threatening to strike. In fact, when I got a bit closer I realised that what I'd assumed was its head, upraised and ready in defence, was actually its stumpy tail (as you can see in the photo). It had tucked its head safely away undercover. Aww, the poor little creature; I could almost see it covering its eyes with its hands and trying to be invisible.

Bibron's burrowing asp (Atractaspis bibronii) also labours under the names of southern stilleto snake, mole viper and side-stabbing snake. Living underground, they like to dine on burrowing reptiles, frogs and little baby rodents. When they encounter a nest of these little cuties, they slither about incapacitating several before indulging in their feast.

Any normal person, I told myself, would just pick it up and carry it outside. But I'm not a normal person. I'm the product of a childhood of indoctrination (by a mother determined to keep her animal-loving offspring alive in a land where almost all snakes are lethal). As a concession, I put aside my poster tube and gently shoved the little creature toward the open door with the broom. It writhed about with weird jerky movements, its head flicking sideways, so rapidly and frequently, it looked as if it had some awful nervous palsy. I'd never seen any snake behave like this.

After I'd persuaded it out the door (and had released the jostling pets), I sat down to identify it.

Oh. It wasn't harmless after all.

In fact, it was quite extraordinary.

It was a Bibron's (or southern) burrowing asp and - I was startled to learn - it and its kin (other burrowing asps) have the longest fangs, relative to skull size, of any venomous snake.
Their huge venom glands (which extend for up to 20% of their bodies) churn out a highly toxic brew that zaps your heart and blood pressure, and induces arterial spasms (now there's a symptom you don't see every day). North African species regularly kill people, but the bite of my common, under-the-table variety just leads to pain, severe swelling, blistering, necrosis, nausea, dryness of the throat and vertigo. You can read, here, the stressful story of someone (sans snake phobia) who made the same mistake as me. But read it LATER, because the really interesting bit is still to come!

You see, what's fascinating is that the impressive fangs of these little snakes are designed for underground use. And you can't rise up and strike in the tight confines of a burrow. So how do they prepare dinner? They've opted for the method favoured by street thugs the world over: they sidle up beside their victim and, without so much as opening their mouths, stab them in the ribs.

Their long fangs, located in the front of their upper jaw, actually lie horizontally in the mouth, pointing back toward the corner of their lips. To make room for this weird arrangement, they've had to sacrifice virtually all their other choppers (making swallowing food a pain - well, actually, a series of wriggles – in the neck). Their fangs have a hollow central tube (like a hypodermic syringe) and the tips are keeled for slicing flesh (all the better to get the venom in). When they want to stab a victim, they only have to shift their jaw a bit to one side, so a fang protrudes from their lips, and then jerk their heads down and sideways: POW!
So when my little house guest appeared to be suffering dreadful trembling palsies, it was actually biting the Hell out of the fluffy nylon bristles of the broom. Just shows, you never can tell.

These snakes are particularly problematic because you can't hold them safely behind the head; they just stab you out of the corner of their mouths. You can see a photo of one stabbing a baby mouse here. The Bibron's burrowing asp is also unusual because it has a sharp spine sticking out of the end of its tail (actually a continuation of its... well, spine). Browsing herpetological websites (oh, the shame), it seems that this anatomical feature further complicates things because care-givers of captive beasts (the species is popular for venom studies) often can't be sure whether they've been spiked by a tail or a tooth!

I included these photos, just in case you don't believe that African rock pythons can kill and eat large beasts (such as heedless huskies). This one has constricted to death an imprudent impala.
Photo by Arno and Louise Meintjes.

And this one is just finishing off a tasty steenbok.
Photo by Alex Griffiths.

Sunday, October 17, 2010

House of Herps No. 11

Welcome to the October edition of the House of Herps blog carnival.

Before I go further, just let me clarify that ‘herps’ are reptiles and amphibians (as in herpetologist), NOT unpleasant, sexually-transmitted diseases.

It’s late in the dry season here.

With no rain for six months, the ground is parched and bare, the trees are leafless, and the wildlife, bony and gaunt.
Temperatures rise into the 40s C (104 F), sapping the last moisture from everything, living and dead.

But the rains may come any day.
Or not.

Almost palpable, spoken silently by plant and animal alike, is the question: can I survive until it comes?

Watching this saga, day after day, as the rainclouds build up and then drift away again, I’ve come to appreciate why humans - in every culture and on every continent - turn to superstition and ritual in a bid to influence Nature.

With so many of the ancient rain-making rituals focussing on reptiles and amphibians, hosting House of Herps seemed a great opportunity to enlist a bit of help in my very non-scientific endeavour to bring-on the rain.

So grab your umbrella and come join our rain-making festivities.

Get ready to rock!
For millennia, people have been boogying for rain.

To call up rain, the Karen people of Thailand and Burma, sway to the beat of 'frog drums', whose bronze tympanum is adorned with rain-inducing amphibians.

Bronze frog drum (2nd century AD). The little lumps are frogs.
Photo by IAMCP30 (Flickr).

In China, it's the dragons (surely up there with dinosaurs as the ultimate herp) who fly up to the clouds for rain, so extravagant dragon-dances are the go. The one you see at Chinese New Year began life as a rain-making ceremony.

Photo by Christopher Chan.

Photo by Marion Doss.

But if you can't snare yourself a dragon, don't worry, a snake will do. To conjure rain, the Zuni and Hopi tribes, of south western USA, hold a live venomous snake in their mouths as they bop. The snakes, released at the end of the performance, act as emissaries, carrying the peoples' prayers to the Gods. The ill-starred Hopi rattlesnake (Crotalus viridus nuntius) is even named after its occasional participation in this shindig.
So today, join Cindy at Dipper Ranch, who - in this grand festive tradition - takes her serpent emissary to a party. How do her neighbours react when their small guest shows its stripes (well, spots actually)? Will they dance?? Find out here.

If you’re having trouble carrying your rattlesnake in your mouth, help is on hand. Join Elizabeth, at Yips and Howls, as she dabbles in the art of rattlesnake transportation and demonstrates a practical alternative. Please bring your own aluminium pail.

But before you get too complacent, thinking that we’ve got rain-production in the bag, pay a visit to Explore Missouri. There’s a problem, you see: the susurration of rattlesnakes is disappearing. Why are our divine messengers growing mute? Shelley explains here.

There's nothing like a bit of bribery to get things done.
And it's a time honoured tradition when it comes to rain-making.

To break a drought, the Nguni Zulu of southern Africa bribe a large python (hugely potent in watery affairs) by slaughtering a pure black goat and laying out its skin; the python slithers in after dark to lick up the fat. Meanwhile, in Sudan, the Lafofa people (whose shaman transforms into a red snake) spill milk on a hilltop for rain-begetting serpents, and, in Nigeria, the Bubbure people dress in sackcloth and ashes and offer munchies to the Rulers of Deep Pools: the crocodile, python and water monitor.

So join me here, at Mainly Mongoose, as I strive to give the gift of freedom to one of these sacred monitors. Unfortunately, it proves a little difficult (toilets and Water Gods just don't mix).

Across at Philly Herping, Bernard contemplates sacrificing chipmunks to placate his missing rattlesnakes. But despite injury, disappointment and obscenities, what he conjures in the end is just as alluring. Check it out here.
The Aztec god Xolotl was allied to death,
fire & lightening. Photo by Pablo Necochea.

Then drop by Beetles in the Bush to gawk at the dazzling creature Ted finds while in pursuit of beetles. Although these critters suffered some seriously bad press at the hands of the Aztecs, the Huichol people of Mexico believed they were agents of the Rain Mother, stirring the clouds for rain. Join Ted as he plans a smorgasbord of delicious offerings for his new family member.

If partying and bribery don't work, why not try rituals.

To save their withering crops, Bangladeshi villagers host a lavish wedding ceremony: for two live frogs. The happy couple - their foreheads daubed with red - are paraded through town in a special basket. After the ceremony (staged on a banana leaf) and plenty of feasting, the villagers release the newlyweds into the village pond.

The ground agama (Agama aculeata) defies its
name by sitting about in trees. Photo by Johann du Preez.
The rain-making rituals of the San bushmen of southern Africa are much more practical: they shoot arrows into the thorn trees. Why? Because the Agama lizard is associated with !Khwa, the Rain. "The lizard lies up on the thorn tree; it keeps its head toward the place where the north wind blows and bewitches the clouds". Only when the lizard is persuaded to get down (by the sound of arrows whistling past its ears) will the rain come.

Join Amber at Birders Lounge as - armed only with a camera – she tries valiantly to disturb some laidback lizards. Of course, there's good reason why these jaunty little guys wouldn't hear the whoosh of a passing arrow...

But perhaps the most innovative ritual is performed by JSK at Anybody Seen my Focus. She enlists the help of a charming anole to enact the miraculous transformation that the bush undergoes after rain. Don't miss it.

It takes time, it takes resources, it takes commitment; but deifying a herp has its payoffs.

Can millions of ancient Egyptians be wrong? (rhetorical question).

The Egyptian crocodile god, Sobeka, was as dangerous and unpredictable as his carnate representatives paddling in the Nile. He engendered fear and awe in his followers, who built him huge temples that housed dozens of bejewelled crocodiles, lazing by their pools. The beasts' remains were even mummified and entombed, with all the care given to family members.
Why go to all this trouble?
Because Sobeka controlled the waters of the Nile. It was He that brought the seasonal inundation, essential to the nation's crops and fisheries.

Sobeka's temple at Kom Ombo. Photo by Colin Goh.

So join Olivia, at Beasts in a Populous City, as she makes a pilgrimage through the hallowed halls of the Reptile House. Share her sense of reverence, and discover why the world's reptiles and amphibians deserve our veneration and awe.

And I'll be watching the sky!

Anybody Seen My Focus
Beasts in a Populous City
Beetles in the Bush
Birders Lounge
Dipper Ranch
Explore Missouri
Mainly Mongoose
Philly Herping
Yips and Howls

Tuesday, October 12, 2010

Magic and the monitor

Outside my window, my dogs are currently leaping up and down at the fence, madly trying to attack a very large reptile.

It's two metres (6 ft) long, sway-backed and very nonchalant, thoroughly conversant with the dog-deterring properties of wire-mesh.

No, it's not a Nile crocodile; it's a Nile monitor (Varanus niloticus), Africa's biggest lizard.

Like all monitor lizards (called leguaans in South Africa and goannas in Australia), these guys are unnervingly opportunitistic predators. Although I like them pottering around (because they chomp the cobras), I'm a bit nervous that this one may munch the cats too. I'm also surprised the dogs are showing such zeal, as Magic's enthusiasm for monitor-hunting suffered a serious setback one day last summer.

It was a really hot day and I returned from the field to find Magic (my husky cross) missing. However, I could hear muffled barking: high-pitched yaps, sharpened by a note of panic. Bewildered, I followed the sound through the backyard to the small outside toilet. I never use this toilet, but I usually leave the cubicle door ajar. Today it was closed, and Magic was evidently shut inside.

But who would shut her in? When I tried the door, it wouldn't budge. Something heavy was blocking it on the inside. After a great deal of struggling (actually - I'm embarrassed to admit - I had to lie in the dirt, brace myself against a tree and use my feet to push the door in ... oh, my shameful lack of upper body strength), I finally managed to force a small gap. I squeezed through painfully, intending to then move whatever was lodged behind the door. Only once I was inside the tiny cubicle - in the warm, fetid darkness - did I realise that Magic and I were not alone.

Crouched halfway up one wall was an extremely large (2 m/6 ft) monitor lizard. It was eyeing me warily; it's blue forked tongue flicking in and out rapidly.

Nile monitors (Varanus niloticus) hang out near permanent water. They're gifted swimmers, taking to the water when threatened (hence my toilet?) and using their long muscular tails for propulsion.
Photo posted on Flickr by Hyper7pro.

Apparently Magic had pursued the fleeing monitor into the toilet cubicle and, in the resulting tussle, one of them had knocked over an old ceramic toilet bowl that was standing behind the door. I don't know how long the pair had been forced to room together (I'd been away about five hours) but judging by the smell – a vile mixture of dog and monitor excrement - it had been a while.

Moving the toilet fixture proved challenging. It was too heavy to drag, so I had to use my feet again. But sharing a tiny cubicle with a highly stressed and impressively armed lizard, along with a large and anxious dog, was unpleasant enough without having to sit on the floor with them. The monitor, now hissing and puffing ominously, responded to my movements by lurching across the cubicle in a long-clawed scramble. Magic, I noticed, leapt out of its way with great alacrity. The creature came to rest on top of the cistern, puffing threateningly and lashing its hefty tail back and forth, alarmingly close to my face. Despite these impediments I eventually managed to shove the toilet fixture a few inches further from the door, and Magic shot out. The monitor was equally keen to leave, although it was kind enough to let me to go first.

Nile monitors call much of sub-Saharan Africa home and also paddle down the Nile into Egypt (hence the name). However, their popularity with reptile fanciers has taken them further afield and a feral population is now enjoying life in SW Florida. Photo by A & L Meintjes.

Magic seemed a little traumatised after this encounter (to be honest, so was I) but, in retrospect, she may simply have been feeling ill. It's now known that monitor lizards have special, venom-producing glands in their mouths. An MRI scan of the world's largest monitor, the Komodo dragon, (don't ask how) revealed six venom glands in its lower jaw, each drained by a duct leading to between the teeth. Researchers have detected venom in at least three Aussie species, but I don't think anyone has yet looked at the African monitors.

Monitor venom is a heady cocktail of ten toxins, seven of which are also made by snakes. Mixed with copious saliva and administered by a bite, the poison prevents blood clotting and dilates blood vessels, lowering blood pressure and inducing shock. When researchers injected rats with monitor venom, they went completely still (the rats, not the researchers... although, thinking about it, the researchers probably deserved it more).

But don't panic! Monitor bites aren't life-threatening; they secrete only tiny quantities of toxin.

But perhaps what's more interesting, is that while the researchers were trying to figure out where and when venom-production first began, they did DNA tests that revealed that monitors and iguanas (a couple of whom are also venomous) are more closely related to snakes than to other kinds of lizards (such as skinks, chameleons and geckos). Monitors and snakes shared a common great granddaddy (who was, of course, toxic) about 200 million years ago.

Nile monitors are surprisingly sociable creatures. They sometimes team up to pinch crocodile eggs (one lures mum away while the other excavates the eggs) and they often spend the winter months snugged up together, hibernating communally within a large rock crevice in a riverside cliff or koppie. Photo by Michael Ransburg.

Saturday, October 9, 2010

Holiday snaps

...and here I am waving goodbye at the airport...

Only kidding.

I'm currently revelling in being back in Africa where the mammals gallivant in the sunshine, flaunting their garish stripes and spots and ornamental tufts.

In Australia, it's all soft-pawed, nocturnal creeping; silent and cryptic and drab of fur (alright, roof-dwelling possums don't seem silent and cryptic at 3am, but you get the idea). Still I guess I'd be cryptic too, in light of Australia's extinction record. The continent has lost 27 mammal species in the last 200 years, and the trend continues...

Despite this horrifying statistic, I very much enjoyed my sojourn in Oz.
I'd like to tell you about all the exciting things I learned at the conference, but I can't. Scientific journals won't accept material that's already published, and posting stuff on a website counts as publication. So unless I want to be lynched, I can't write about anyone's research results. A bit frustrating.

However, I can write about the day trip. When the conference delegates began swooning from information-overload, the organisers packed us up and bussed us out to Paruna Wildlife Sanctuary, a woodland reserve east of Perth. It's owned by the Australian Wildlife Conservancy who assiduously lay out poisoned baits for those arch villains, the red fox and feral cat, and then reintroduce the region's small (sorry, medium in Australia) endangered mammals (e.g. black-flanked rock wallaby, southern brown bandicoot, brush-tailed bettong and tammar wallaby).

Of course, the stomping feet of 200 behavioural ecologists would put the wind up any self respecting animal (including your average hermit) so we didn't actually see any of the aforesaid rarities. Nevertheless, we had a jolly time pottering about peering at whatever oddities interested us. You could see the ant specialists lying on their stomachs beside obscure-looking holes, the spider aficionados craning their necks beneath wisps of web, and the ever-present birders hotly debating the identity of something small, brown and very far away.
I breathed the eucalyptus-scented air, tried not to look for hippos in the dam and snapped poor-quality photos of the many wildflowers (which I'll now inflict on you).

The Paruna Wildlife Sanctuary forms a 2000 ha corridor linking two national parks.

This little sundew digests ensnared bugs to get the nutrients which are unprocurable from the ancient leached soils.

Like all kangaroos, the western grey (Macropus fuliginosus) is a master at milk manufacturing. Because the needs of a growing joey change with age, mother roos fine tune the chemical composition of their milk to fit the bill. But what's really amazing is that roo mums produce two different kinds of milk at one time.  One teat secretes milk suitable for the big joey hopping at foot, while the other caters for the smaller youngster who's still fixed within the pouch.

The Australian ringnecked parrot (Barnardius zonarius) is the most common parrot species in Perth. I have to admit that, living in Africa, I miss the ubiquitous presence of parrots: the colourful squabbling, the brilliant flashes as they clamber and dangle in the foliage, the fluting whistles of lorikeets and the wide-horizon shrieks of cockatoos.



Tuesday, October 5, 2010

When spring comes unsprung

Spring is here!
In theory.

It's just that spring here isn't like spring in Other Places.

You can forget the rising sap, unfurling leaves and frolicking bunnies and chicks (alright, I admit I've never actually experienced a Northern Hemisphere spring, but I've seen the Easter cards...)

Here spring is more like an intense bout of schizophrenia.
At night winter has a monopoly, with temperatures dropping to 8 C
(46 F), but as soon as the sun sneaks over the horizon, summer leaps in and the mercury rockets to the mid 30s C (95 F).
And the weather's not the only one refusing to take its meds.
After five months without rain, the bush is leafless, parched and grey. As you'd expect. Then whoosh (that's a figurative whoosh, not an audible whoosh), all the knob thorns burst into flower.

Knob thorns (Acacia nigrescens) are the dominant tree species here, so if they decide to bloom prolifically, when everyone else is playing dead, it's rather startling.

The knob thorn gets its name from its... er... knobs, which grow on the trunk and branches of young trees. Each knob is tipped with a single thorn, presumably to spike large herbivores.

In Africa, acacias are called thorn trees (rather than wattles) because of their weaponry. My tree guide (South African) puts it bluntly: 'Australian acacias are always spineless'. Even I feel that this is a trifle harsh.

All the local browsers (giraffe, kudu, bushbuck and impala) enjoy munching knob thorns, but I hadn't realised how sought-after the species was until I tried to take a close-up photo of its flowers. No go. Despite an exhaustive search, I couldn't find a single branch growing within my reach (kudus are considerably taller than me!). I trust you appreciate my dedication to blogging, as I had to dodge speeding traffic to snap an un-nibbled, highway-side specimen.

Hard-won knob thorn flowers.

With such a profusion of blossom, the local giraffes are looking rotund and smug. During the brief (2-3 week) flowering period, knob thorn flowers make up 25% of their diet, and they're currently swanning around dusted in golden pollen, and sometimes wreathed with creamy blooms. It's been suggested that giraffes may act as pollinators for the knob thorn, since the trees produce many more flowers than they need for seed production. However, research undertaken in Kruger National Park found that knob thorns growing in giraffe-free localities produced more seed than their giraffe-nibbled counterparts. And within trees munched by giraffes, seed-production was far greater in branches located above the giraffe's reach than in the branches they could access.

Munching knob thorn flowers isn't as pleasant as you'd think. They contain three times more tannin than the leaves. Tannins (which have that awful drying, astringent effect in your mouth) bind with the plant's proteins, making them indigestible.

Are giraffes pollinators or flower predators of Acacia nigrescens in Kruger National Park, South Africa? P.A. Fleming, S.D. Hofmeyr, S.W. Nicolson and J.T. du Toit. Journal of Tropical Ecology (2006) 22:247–253.

NB: I wrote this post a couple of weeks ago, but I was so busy emulating decapitated poultry (during the lead up to my overseas trip) that I didn't get around to posting it. Sorry!
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