The world's largest crocodile in captivity is celebrating its 120th birthday — we think.
That's because nobody really knows the age of Cassius, a 5.48m saltwater crocodile that lives in Marineland Crocodile Park on Green Island in the Great Barrier Reef. But he's old.
Crocodile researcher Graeme Webb was in his 30s when Cassius was captured in a rope trap in the Finniss River on La Belle Station, 81 kilometres south-west of Darwin in 1984.
He and crocodile scientists Charlie Manolis and Karen Dempsey were contracted to capture the beast for the station owners, who were losing livestock.
"He was a big old gnarly crocodile then … crocs of that size are not normal," Professor Webb said.
"He was 16 feet, 10 inches with at least another 6 inches of tail missing and a bit of a snout missing."
Cassius was dragged out of the trap with a buffalo-catching vehicle, into a cattle truck and moved into a purpose-built pond at LaBelle Station, he recalled.
"The big issue here is to get the animal out to stop it struggling and get it somewhere where it could recuperate," Professor Webb said.
He said "big crocodiles" were rarely seen back then.
"And nobody had much experience … dealing with them as live animals.
"Trying to catch him was very difficult because you really had to outsmart them.
"In those days, adult crocodiles that survived the hunting period were very wary."
Hunting was outlawed in the Northern Territory in 1971.
Professor Webb recently visited Cassius, observing he had grown more, "which is unusual for a big croc".
"He was big and old when we caught him and 38 years later he's still alive.
"That's giving us serious knowledge on longevity."
So how old is Cassius?
Professor Webb said Cassius was between 30 and 80 years old at the time of capture.
"He's quite possibly over a century — maybe 120 years," he said.
Professor Webb said Cassius's neighbour Sweetheart, who was accused of many croc attacks in the 70s, might have been blamed for some of his boat-biting antics.
"He had the tip of his snout broken, which you can get from attacking a propeller," he said.
How did Cassius get to Green Island?
Queenslander George Craig bought Cassius a few years after he was captured, and in 1987 transported him to Green Island, 28 kilometres offshore from Cairns.
The station owner approached Mr Craig after learning of his fascination with crocodiles.
The 93-year-old's grandson, Toody Scott, is now a crocodile keeper where Cassius lives.
"When he first set eyes on him, he knew Cassius was something special," Mr Scott said.
A deal was done, Cassius was manhandled onto a truck and spent a week on the road to Cairns before being ferried across to Green Island.
Mr Scott said Cassius's estimated age of 120 years was based on international research on large reptiles.
Cassius holds the Guinness World Record since 2011 for the biggest croc in captivity.
Mr Scott said Cassius had had some big-name visitors, including the late Queen Elizabeth II, Chinese President Xi Jinping, the King of Thailand and former prime minister Scott Morrison.
"He still has a lot of spark in him," he said.
"Generally, the big old reptiles tend to sort of be pretty docile and disinterested.
"Cassius is always up for interaction. He's one of our liveliest crocs and very engaging.
"Anytime he sees you, he wants to come and say g'day and his eyes light up."
Will Cassius last another 120 years?
"I'd like to think he's got a few more years left in him," Mr Scott said.
"The best way to a crocodile's heart is his stomach and I'm sure he'd love to make a meal of every single one of us."
And what's in the birthday cake? A big tuna or a chicken are Cassius's favourite treats.
