David Whitley discovers how northern Australia has turned from shooting crocodiles to showing them off to visitors.

Swimming in front of us is one of the finest killing machines ever devised by nature. Even its swimming strokes are menacing; the slow, deliberate movements of the tail cut through the water in eerie silence. And nothing else on the Adelaide River is stupid enough to come near it. The estuarine (or saltwater) crocodile is an amazing creature. It is our closest living reptilian link to the era of the dinosaurs, and the essential design of the saltie hasn’t changed in millions of years.

It hasn’t changed, because it hasn’t needed to. The saltwater crocodile is the undisputed king of all the terrain he chooses to inhabit; no other creature can bite with such force and its cool, calculating manner commands total respect. Crocodiles can wait for weeks, monitoring the behaviour and routines of their prey and remaining undetected. Then, when they’re ready to pounce, the victims will be goners before they even know the croc is there. But being such effective killers almost lead to the saltwater crocodile’s downfall. Until the 1970s, crocs were seen purely as a menace in northern Australia. They were shot almost indiscriminately by well-meaning folks wanting to make the waterways safer, and hunters taking them on for sport.

Since that time they have been protected and although many still see them as a deadly nuisance, others have worked out how to make good money from them. To put it simply, tourists like seeing crocodiles in action. And given that the Adelaide River near Darwin is absolutely teeming with crocs, there are few better places to get up close. Going for a swim or a walk along the banks would, of course, be the act of a suicidal maniac. But going out on a boat and watching them come to you is a different matter altogether. A number of different cruise operators plough up and down the river, but the schtick is essentially the same. Boat goes down river; crew dangle meat from a pole at the top of the boat; crocs come and get it.

Watching them do so is fascinating. Some just aren’t interested. They stay where they are on the banks or neck deep in the shallow water. Others spot a free feed and slide away from their spot, creeping through the water. When they reach the side of the boat, you can see them weighing up their options. They stare at lunch, plotting the best way of getting it like a pool player working out how to extract himself from a tricky snooker. And then they go for it, jumping out of the water, often level with the top deck of the boat. It’s an astonishing sight – eyes never off the prize, tail powering them out of the murky river and mouth opening in preparation to snap shut around the meat.

This isn’t a case of forcing the crocs to do tricks – the jumping is a natural behaviour, used to snatch unsuspecting birds from low branches – but it’s a perfect display of why this ancient predator is not to be messed with. And it’s far better to shoot them with cameras than rifles.

More photos here