Ranger Chris Peberdy’s job looks easy — just hook the white rope loop through the 3m croc’s mouth behind its teeth — but it’s anything but.

Balancing on the floating trap in Darwin Harbour, Chris is forced to clamber back and forth as the croc dives from one end of the cage to the other.

Falling off the trap isn’t an option — if this crocodile is inside the bars, then there are any number of others on the outside, beneath the water lapping against the edges.

The white rope catches — but it’s not far enough back in the mouth, and a simple deathroll unlodges it again.

Then veteran wildlife ranger Tommy Nichols’s voice cuts across.

“Tap him a bit harder with the stick and then snag him and pull him tight,” Tommy says.

And after another couple of goes, it works, and the massive croc is zip-tied.

It’s clear Tommy’s domain is out on the water.

And why not? He’s been doing it for 38 years.

The now 64-year-old grew up in the Territory, and always wanted to work with wild animals.

But that wasn’t the thing that people did — so instead he undertook a diesel fitter fuel injection apprenticeship.

However, after several years and many applications, Tommy finally found himself in his ideal job, working for NT Parks and Wildlife.

“Back then there was no real croc team because we didn't need it — it would have been 20 years ago that the whole crocodile section got started up,” he says.

When the team did get started, it was small.

“We had two blokes and s**t equipment and now we’ve got five blokes and good equipment,” Tommy says.

Suddenly, the croc starts thrashing again and the cable-tie snaps.

Tommy climbs over to put another on, and the job is truly underway.

Because the crocodile is too big to squeeze through the trap’s top vent Chris opened to put the rope through its snout, it has to be lead around the front of the boat and winched up the side.

As it deathrolls in the open water, the second cable-tie snaps, and, now that the protection of the cage is gone, Tommy stops talking.

Catching wild crocodiles is not without its risks, and no one knows this more than the original croc ranger himself.

Almost 15 years ago, Tommy was tying a rope around a croc’s mouth when it flailed and snapped, latching onto his hand and wrist.

With a bit of a shake, and a bit of luck, the croc opened his mouth and Tommy managed to wrestle his wrist free — only to have his left ring finger and pinky become trapped in the animal’s jaws.

The croc then went into its natural predator mode, shaking until he tore the fingers clean off.

Tommy was two digits down.

“I was a bit apprehensive about what I was going to do, but then when I got back to work — the first croc was in the Daly River and he was a 4.2m,” Tommy says.

Once he’d proved to himself he could work with only three fingers on his left hand, stopping his intrepid line of employment wasn’t an option.

“It’s about having a healthy respect for the creatures you’re dealing with,” he says.

“It’s good to always have a healthy fear. They’re like humans. You know what they’re capable of but you don’t actually know what they’re going to do next.”

Despite the major injury, Tommy doesn’t let it get to him.

“I’m right-handed so it doesn’t affect me much — I can only count to eight now though,” he jokes.

“And let’s just say work practices improved pretty dramatically after that.”

His injury, unsurprisingly, coincided with the moment cable-ties were brought in to close the crocs’ mouths, rather than ropes.

“With the ropes, we used to have to get up close to wrap them around,” Tommy says.

“Now we don’t need to have our hands anywhere near them to even do it up.”

The croc writhes against the side of the boat as it is slowly winched out of the water.

A third zip-tie is tightened around its deadly jaws, and Tommy quickly puts duct tape around the rest of the snout and head, taping a piece of old carpet tight against its eyes.

“They’re like most animals — when they can’t see what’s going on, they calm down,” he says.

As the longest-serving member of the crocodile management team, it’s not surprising Tommy is well-renowned — he commands a healthy respect from his colleagues, just as he has for his crocs.

People from around the country come to him to learn how to deal with problem crocodiles.

Tommy works with indigenous communities and has even travelled to Timor and the Solomon Islands.

And why wouldn’t he travel — crocs themselves have been found hundreds of kilometres out to sea and are understood to move around between countries north of the Tropic of Capricorn.

The respect his team have for him is clear from how they speak about him.

“Growing up in Katherine as a kid I used to have pictures of Tommy from the newspaper on my bedroom wall,” Chris says.

“Kids down south had footballers, but I had Tommy.

“There’s no one who knows the job better than Tom.”

Taped up, the crocodile is slowly towed around the outside of the boat and pulled up over the ramp and hauled inside the vessel.

Now on the floor, the reptile’s size is only made more obvious, and standing room becomes a little more difficult.

Chris puts pressure on its head while Tommy kneels and ties its back feet together.

“Once they realise they’re overwhelmed, they don’t try anything,” he says.

The croc is the second of three the pair will catch on this trip on the harbour.

Already this year the Parks and Wildlife NT team have captured 300 salties, of all different sizes.

“Some people ask why we don’t leave the small ones, but the small ones will only grow into big ones,” Tommy explains.

The capture and removal of so many crocodiles is obviously saving lives of Territorians, but Tommy doesn’t think like that.

“All we’re doing is reducing the numbers and reducing the risk,” he says, downplaying his important role.

“If we didn’t have the crocodile management system we have, the chances of more fatalities would be extremely high.”

And Tommy knows about fatalities — he’s the one who is normally tasked with trapping, killing and performing the autopsies of crocs that have attacked humans.

Finding the remains of children is, emotionally, the hardest, he says, but doesn’t elaborate much further.

But, these are the tough sides to the job.

The aquamarine Timor Sea races by underneath as the boat speeds along — and it would be hard to imagine a more exhilarating day at the office.

With the croc now trapped and tied inside the boat, ranger Chris climbs back over onto the croc cage, rebaits it with more meat, and sets the trap again — ready to catch another potentially monstrous killer.

And once he’s back in the boat, Tommy hits the ignition and the pair race towards the next cage, ready to start the whole process again — both filled with a healthy fear of one of Australia’s most dangerous predators, keeping them alert day in, day out.