TUNNEL VISION
Undara’s awesome lava tubes
THIS IS FAST FOOD FOR SNAKES – about 50 kilometres per hour to be precise. At the mouth of Barker’s Cave in Undara Volcanic National Park, thousands of flying microbats whir and whiz all around us on their way out for an evening’s forage. Standing in an eerie cloud of high-speed, virtually invisible bats, we trust their aerial wizardry extends to not slamming into our faces. The snakes are foraging, too. Barker’s Cave is their drive-through McDonald’s, except it’s the food that’s driving through. Draped on nearby branches, brown tree snakes are poised to pluck a mid-air bat snack as the ghostly gazillions zoom by. The tree is so well-placed you could almost believe the snakes had it installed, but it’s a perfect example of environment shaping behaviour. The trees grow there because of rich volcanic soil in the gully at the cave mouth, and the snakes are just smarter than you’d think. We’ve just had sunset drinks, admiring distant dead volcanoes poking above plains of trees glowing an almost luminous green in the fading golden light. “This is when I get to say: to the Bat Cave!” our guide Wes announces as soon as we quaff the plonk. A short minibus ride later we’re staring into what looks like a haunted railway tunnel. A flat dusty floor vanishes into pitch darkness beyond torchlight, which Wes uses judiciously to minimise alarming the countless speeding bats. Barker’s gloomy grey walls are lavishly tattooed with silver-white streaks and slashes. It could be a science fiction or horror movie set, but it’s something much more exotic – one of Undara’s known 69 lava tubes, rare geological marvels in Queensland’s Gulf Savannah country only accessible by guided tour. The tubes date back 190,000 years, when an actively volcanic landscape seethed and bubbled with up to 1200°C lava. Oozing from now-extinct Undara volcano at 1000 cubic metres a second, it covered 1550 square kilometres up to 20 metres deep. Some of it cooled and solidified around hotter, faster-flowing lava, which left hollow tunnels behind as it streamed through. These tube-like caves (or cave-like tubes) could have stayed forever sealed and empty, hidden underground. But roof collapses in ages past created gullies with tube entry points – and a whole way of life. Cooler than the red-dirt plains above, these gullies (evergreen vine thickets) preserved primeval rainforest vegetation such as figs, vines and bottle trees that elsewhere gave way to eucalypts as the climate dried. Descending into a thicket on Undara’s daytime tour feels like a step back into deep time. A huge vine-strewn fig and steep rock walls conjure a prehistoric vibe; it feels like a dinosaur’s lounge room. A lone wallaby, escaping the day’s heat, watches us from a shaded ledge. Scrub turkeys ignore us completely, noisily nest-building in the tangled undergrowth, absorbed by what they’ve been doing for millennia. Capping it all is the Archway, towering above us and jagged with sharp, shiny rock-faces. A remnant slab of tube roof, it bridges an ancient collapse that opened nearby Ewamian and Stephenson caves. Stephenson is the largest tube on the tour, gaping 25 metres wide. Penetrating tree roots dangle from the
Descending into a thicket feels like a step back in time. A huge vine-strewn fig and steep rock walls conjure a prehistoric vibe; it feels like a dinosaur’s lounge room.
20-metre ceiling and bats nap anywhere they can. Tonight they’ll venture 20 kilometres or so to feed, guzzling up to 100 mosquitoes a minute. Always eating out, they’re missing a choice meal at home. Sharing the walls, perfectly edible granny’s cloak moths would be better named invisibility cloak moths. Wes zeroes in on their furiously vibrating wings, a trick to scramble the bats’ echo location so they can’t be found in the dark. Standing in overhangs, collapsible metal rods are primed to detect the slightest roof movement – which has never yet happened. The walls swirl with patterns of brown (iron oxide), grey (basalt) and white (calcium carbonate). “Who can see a giraffe?” Wes asks, flashing a torch on the wild carnival of shapes. On the other side of the Archway, Ewamian (pronounced yura-min) Cave is named for the area’s traditional custodians. In their language, ‘undara’ means ‘a long way’, appropriate for the world’s longest known lava tubes (160 kilometres). But there’s no history of human habitation. The Ewamian avoided them, citing bad spirits – a good move as carbon dioxide can reach dangerous concentrations inside, exhaled by dangling tree roots. This bad air, Wes speculates, may even be the spirit lore’s origin. The region’s first white settlers also let the tubes be. In fact they were largely ignored until a geological survey in 1960, a century after becoming part of the Collins family’s Rosella Plains cattle station. As scientists increasingly found how special the tubes were, fourth-generation boss Gerry Collins became inspired to diversify into eco-tourism and share his property’s remarkable geology with the world. Tube tours began in 1990, two years before Undara Volcanic National Park was created around the site. Today the Collins family operate Undara Experience nearby, combining tour HQ and visitor lodge with a restaurant and event space. Of nine non-tube self-guided walking trails in the vicinity, the highlight is a 2.5-kilometre hike around the elevated rim of Kalkani Crater. A short drive from the lodge, this long-dead volcanic vent looks like the Moon with trees, a forested dish overlooking the undulating hills of a once-explosive landscape. But it isn’t the weirdest sight among the gum trees; that would be the trains. When Gerry Collins built the lodge his masterstroke was the purchase and conversion to accommodation of 11 disused vintage Queensland Railway carriages – some 130 years old – found languishing on a siding in Mareeba, near Cairns. “They reckon there’s a ghost in ’em,” Wes hints, but my sleepover in a historic red carriage – complete with original luggage racks – proves supremely relaxing. Morning, graced with birdsong, whiptail wallabies and red-tailed black cockatoos, includes a cooked camp-oven breakfast with damper and billy tea, the perfect plein-air precursor to a tube tour. Somehow it all fits together: old trains, older tunnels and a journey somewhere unforgettable.