How old was Cassius the crocodile? Scientists are trying to work out the birth date of the 18-foot ‘living dinosaur’ who died in Australia at a suspected age of 120

Scientists in Australia are now searching for the true age of Cassius, the recently deceased saltwater crocodile.

The 5.5 meter long crocodile was captured in the 1980s and lived in the Marineland Melanesia Crocodile Habitat on Green Island, off the coast of Cairns, Queensland.

Experts estimated his age at the time at 80, meaning that by the time he died last weekend he was 120 years old or perhaps even older.

However, this was only an estimate, so after his death, scientists conducted an autopsy in an attempt to determine his true age.

Tragically, Cassius died just weeks after his ‘best friend’ George Craig, his veteran crocodile dealer, left the island.

In a post on Facebook, his keepers at the nature center said: ‘He was very old and was thought to be older than a wild crocodile.

“Cassius will be greatly missed, but our love and memories of him will remain in our hearts forever.”

Sally Isberg, founder of the Center for Crocodile Research in Australia’s Northern Territory, believes Cassius’ true age can be revealed by studying the bones.

Cassius was known to prowl the waterways of Australia before his life before being brought to Marineland Marineland Melanesia Crocodile Habitat. Tragically, the crocodile died just weeks after his ‘best friend’ George Craig (pictured) left the island

Cassius, the world's largest captive crocodile, is pictured at Marineland Melanesia on Green Island, Great Barrier Reef, Cairns, Australia

Cassius, the world’s largest captive crocodile, is pictured at Marineland Melanesia on Green Island, Great Barrier Reef, Cairns, Australia

As an animal ages, the bones gradually develop layers or ‘rings’ that, like tree rings, can be counted to find out their true age.

Samples of the bone are now being sent for analysis, although Dr. Isberg said she is concerned that growth rings may not be “easily detectable.”

“My plan is to send it to a laboratory that can cut it and look for annual rings, just like trees,” Isberg said. ABC News.

Of course, no bone analysis could be performed while the animal was still alive, so only once the animal is dead can Cassius age properly.

Dr. Isberg said a routine necropsy – a surgical examination of a corpse – showed there was no “causal cause of death.”

In other words, the 1,300kg Cassius – often heralded as the world’s largest pet crocodile – simply died of old age, it is thought.

Although the next step is to analyze the bones, the results can take months to come back and may be inconclusive.

Samples have also been taken from his major organs, while the skin and head are also being preserved.

George Craig of Green Island Marineland Melanesia (pictured) feeds Cassius who has died aged 110

George Craig of Green Island Marineland Melanesia (pictured) feeds Cassius who has died aged 110

Unfortunately, a health examination of Cassius conducted last year found that there is “no reason to believe that Cassius will not live for many years to come.”

Saltwater crocodiles are very dangerous to humans and are responsible for at least several dozen attacks on humans each year.

Wildlife experts generally say that saltwater crocodiles live more than 70 years, but no more accurate figure is known for this species.

Professor Adam Rosenblatt, a biologist at the University of North Florida, previously reported this Living Science that those in captivity tend to live longer.

“My own educated guess is that the maximum lifespan for crocodiles as a group is between 100 and 120, but they would only reach those ages in captivity,” he said.

‘In the wild, most crocodilians probably don’t live longer than 60 years.’

The oldest known crocodile, Freshie, was estimated to be 140 years old after being captured by Steve Irwin in 1970.

As the name suggests, Freshie was a freshwater crocodile, a species that was not thought to live as long as saltwater.

Saltwater crocodiles are very dangerous to humans and are responsible for at least several dozen attacks on humans each year

Saltwater crocodiles are very dangerous to humans and are responsible for at least several dozen attacks on humans each year

Cassius is the largest crocodile ever captured alive in Australia. He was 5.48 meters long and weighed approximately 1,300 kg (2,870 lb).

Cassius is the largest crocodile ever captured alive in Australia. He was 5.48 meters long and weighed approximately 1,300 kg (2,870 lb).

Cassius had lived in the Marineland Melanesia Crocodile Habitat since 1987 after being captured in the Finniss River, near Darwin, in 1984.

At the time, Cassius was believed to have been between 30 and 80 years old, an estimate based on a size comparison with crocodiles kept in captivity since birth.

In 2011, Cassius set the Guinness World Record as the largest living crocodile in captivity.

The crocodile had an especially close bond with his keeper Craig, and the pair sat quietly together for “hours at a time,” said Toody Scott, a former keeper and Craig’s grandson.

“For the last few years, George got around on a mobility scooter and every time he got near the fence, Cassius would come to him,” Scott added.

Cassius was touted as a ‘living dinosaur’ because it looked so old – making it a particular draw for tourists.

Marineland Melanesia is a small habitat that is home to ‘problematic’ crocodiles considered a threat to humans.

Craig founded the center in 1971 after 18 years of safely capturing and translocating crocodiles to help prevent attacks on villages.