Outback: How to kill a cane toad kindly

A crocodile sunning itself on the rocks at Boodjamulla National Park. Photo / Queensland Environmental Protection Agency

Death by freezing is the most humane way to kill a cane toad. And if you think that's cruel, as I did, remember it takes just one cane toad to kill a crocodile. The croc dies from a bad case of indigestion. The toad only goes to sleep as it cools down and freezes solid overnight.

And cane toads aren't just a threat to crocs. Most large lizards in the Boodjamulla (Lawn Hill) National Park in the remote extremes of Queensland such as goannas have died off having made the mistake of treating the toads as a tasty meal.

This we learned on an early morning guided walk in the outback oasis - trailing the banks of an emerald green gorge. We'd lucked in when we arrived at the basic campground at Lawn Hill Gorge - hundreds of kilometres from the nearest centre - to find a national parks celebration in full swing and a world renowned palaeontologist right on site.

Uniformed park staff with clipboards arrived at our tent as soon as we'd set up to register us for a dawn walk, and a guided tour of the nearby Riversleigh D site - a World Heritage Site and one of the world's great fossil sites.

It wasn't quite what we had in mind when we drove 650km over dirt roads to get to Boodjamulla, which is near the Queensland/Northern Territory border. But we were to learn far more about Boodjamulla, its spectacular water source, and the local microclimate than we ever could left to our own devices.

Large reptiles may be in short supply, but birds are not. Fifty-three species of birds provide a constant cacophony.

The bowerbird's fantastic wooing of the female captured our imaginations. The male collects items of its favourite colour, which it builds into a boudoir to attract females.

One such bird our guide found had a penchant for stealing white limestone chips that the national parks department had trucked in for its new picnic table areas. It topped the creation with shards of broken green glass left behind by a less than environmentally conscious camper.

In such a dry environment as the Australian outback it's a surprise to find water anywhere, let alone a 27m deep gorge. Boodjamulla, however, marks the border between sandstone and limestone country. During the wet season water soaks into the aquifers and is pushed up through springs to feed the Lawn Hill Gorge.

Faced with so much water we hired canoes to paddle up to the Indari falls, a local tourist attraction, then carried them up a short track and to the very top of the gorge. High above trampers waved from the spectacular lookout.

The tour of the nearby Riversleigh D site opened our eyes to what, without some knowledge, would seem like a rocky outcrop - although there is a reasonably interesting interpretative centre. Riversleigh's fossil beds span more than 60sq km.

The waters calcified everything that fell in for the last 24 million years, producing some of the best fossils of anywhere in the world.

In a convoy of cars we set out for the Riversleigh D fossil site where 200 previously unknown species of vertebrates had been discovered at the very site where we stood.

We were regaled with stories of how they'd experimented with everything from vinegar to gelignite to expose new fossil remains and our field trip left me with the ability to identify fossilised bat bones - although I have to admit that I'd have walked straight past the crushed crocodile head fossil if it hadn't been pointed out.

Back at base camp, the best way to spend a hot afternoon is to take a dip in the lake-like gorge water - although it was nigh impossible to get over the nervousness of swimming in water where crocodiles sunned themselves on the banks.

While saltwater crocs may enjoy a feast of tourist, the freshwater varieties are more interested in eating large fish. Only once in the history of the park had a swimmer been attacked, our parks guide John Prince said. But once the reptilian beast realised that the trainer and human foot it had in its jaws didn't taste right, it let go. Or so we were told.

Having a guide had its advantages. We learned in graphic detail how to kill a cane toad humanely, and also that we were wasting our time searching the gorge edge for frogs. They were hibernating in the toilet cistern.

The other wildlife I chose not to think about too much was catfish, which could mistake a human toe for food, and the Barramundi, which grew to 1m in length.

There has been human habitation at Boodjamulla for tens of thousands of years and the Waanyi Aboriginal people have strong cultural ties. Locals had promised a cultural show on the final night of Dr Archer's visit - but sadly, although the campfire went ahead, the death of a local meant the Waanyi stayed away.

Foreign tourists are as rare as goannas in Boodjamulla. More than 90 per cent of the people that make it there are Aussies - mostly due to its remoteness in the far reaches of northwest Queensland, 350km northeast of Mt Isa, which in itself is remote.

We arrived by a roundabout route via the McArthur River airport in the Northern Territory and a 650km dirt-road drive. Shops and petrol stations are hundreds of kilometres apart in this part of the world and may be closed if the tanker hasn't turned up. This meant carrying extra petrol, extra water and two spare tyres. We carried enough food for our week out bush.

Although there was no electricity or cooking facilities at our campsite, there was a clean toilet and shower block. Camp fees are A$4.85 ($6.20) per person per night. When we weren't being rounded up by the jolly hockey sticks girls and their clipboards, there were a series of walks ranging from 2km to 7km - taking in the falls, the local sandstone ranges and the Wild Dog Dreaming cave paintings - something I'd never seen before.

Diana Clement made her own way to Boodjamulla.

CHECKLIST

Getting there: Charter companies fly into Adels Grove or
it's a five-hour drive from Mt Isa.

Travel tips: The best time to go is during the dry season from May to October, when temperatures range from 12C-28C. Supplies available at Adels Grove.

More information: Visit the Queensland National Parks website and search for Boodjamulla.