Smile at crocodile on this cruise

Adrift on the muddy waters of Proserpine River, the tension is building steadily. The mood seems to heighten as the silence increases to a roar. The guests onboard are alert. We are deep in the habitat of Crocodylus Porosus, the estuarine or saltwater crocodile, the apex predator of the Whitsunday coast wetlands.

Having already approached two 2.5m specimens, Proserpine River Eco Tours tour manager, Steve Watson, has cut his vessel's engine. Only the cry of a water bird breaks the silence.

And then the sighting comes. A 'salty' about 3.5m long is basking among sun-splashed mangroves just 30m away. Guests exclaim in almost perfect unison. Strangers swap excited looks. Gestures are made to be sure the whole group has spotted this 240 million-year-old descendant of the Triassic Age.

It is a primal moment and appears to inspire fear and satisfaction in all present.

Meanwhile, the reptile braces itself slowly and automatically as the boat drifts closer. A slight tilt of its head reveals a telltale and enigmatic smile. Then comes a lightning-quick flash of gold and black scales as the croc plunges into the river and is gone.

"It's probably the fastest animal in the world over two metres," Steve says. "It can launch two thirds of its body out of the water. However, it can't sustain its speed on land.

"The jaws can exert seven tons of pressure per square inch," he continues. "But the stomach is only the size of a soccer ball. That's why salties will shake their heads and roll; it's to rip chunks off their prey."

We are told Australia's estuarine crocs will also store the rotting carcasses of prey, including wallabies, kangaroos, birds and even water buffalo, in order to feed at a later time.

The rich intertidal ecosystems and fresh water wetlands of the river provide the perfect setting for the tour; some of which has guests wagon-riding past billabongs and through teatree swamps.

Fittingly, the name of nearby Goorganga Plains roughly translates from an indigenous word to mean "home of the big crocodiles". Steve estimates Proserpine River's crocodile population to be well over 100 with the largest specimen about 5m. That would make the local mud crabs pretty cautious crustaceans as they're said to be a favoured crocodile canape.

The mood on board changes as we approach a nesting site for the river's crocs. We can see 20cm wide slide marks in the bank and we're told a 3.5m female is probably waiting patiently under the boat for us to leave.

Then comes the history of a 5m croc that was removed from the river in 1989 after it became too aggressive with the locals' fishing dinghies. Further commentary tells of photographs floating around the region showing crocodiles shot in the 1930s that measured in at 10m long and 3m wide; that's just slightly bigger than the boat we're cruising in. Those sly crocodile smiles start taking on new meaning.

"Human bone takes on the consistency of very rubbery gristle after one week in a crocodile's stomach," Steve kindly points out.

"The chance of attack however is fairly remote. More people were attacked by vending machines in Australia last year than there were crocodile, shark and snake attacks combined." Steve figures 35 people were crushed to death in the year 2000 after irate arguments with vending machines.

Official records show that 97 crocodile attacks resulting in 29 fatalities have occurred in the time of Australia's written history. Often the incidents involve dangerous human behavior like swimming or cast netting in known croc habitats, swimming at night where crocs are feeding and swimming in croc country under the influence of alcohol.

Meanwhile, Whitsunday crocodiles will soon be more active as the summer season approaches. They may even be island hopping and looking for romance. Breeding season is from late September through October. The start of the wet season is also a time when crocs may swim through open water, from one estuary to another, looking for a mate.

Although the Whitsunday area is better known for tropical beaches, blue water sailing and diving over coral reefs, the region nonetheless has large areas of island-based crocodile habitat: the mangrove-lined estuaries. In the past two years two offshore sightings have been reported. One croc, said to be 4m long, was seen 500m off shore between Pigeon Island and the residential area of Cannonvale. That's 2km west of downtown Airlie Beach.

In another report, a large crocodile was observed swimming off Long Island, which is only 1km from the coast in places. Estuarine crocodiles however have been reported up to 70km offshore and hundreds of kilometres inland. Two fatal attacks from the 1980s occupy a place in Australian folklore.

One was on the unfortunate American model Ginger Meadows who was killed swimming at the base of Kings Cascade in North Western Australia. Horrific tales of the determination shown by the crocodile to hold on to its prey became the stuff of legend.

The death of Beryl Wruck in waters near Daintree Village in North Queensland is also a well-known story. In this case, a group of revelers were wading late at night with perhaps less than perfect judgment. Wruck is said to have been targeted by a large crocodile when she became the smallest "prey" by crouching to splash herself with water.

Whatever the case, the prospect of being eaten by a finely-evolved predator triggers a primal reaction in people. The estuarine crocodile, however, has been protected in Australia since the 1970s after hunting reduced the species to an endangered level.

In an anniversary that should be noted, 2004 marks 30 years of protection for the species.

"When crocs were shot, it's fairly likely they were destroyed just because of their normal behavior," says Steve at the Eco Tours.

"Hopefully, as people come to understand more about them, more rational decisions will be made about their management. Crocodile numbers are coming back to healthy levels but it's certainly not a population explosion. People are also moving deeper into croc territory and crocs are becoming more used to people. We have to remember that in many places people have learned to live quite happily with crocodiles."