World’s largest crocodile — measuring nearly 18 feet long — still growing as it hits stunning age milestone

An Australian wildlife park claims to have the world’s largest – and possibly oldest – crocodile in captivity, estimated to have lived for 120 years, with plenty more time to go, according to his handlers. 

“Cassius is such a magnificent, beautiful boy, and he’s obviously got a major history to tell us,” Sally Isberg, managing director at the Center for Crocodile Research in Australia, said in a video interview shared with Fox News Digital.

“He’s a happy, healthy boy,” she added. “He has such a personality. He gets called over to one side of the pen and is just happy to wander over… he’s an absolutely fascinating character.”

Captured in 1984 near the city of Darwin and transferred to Green Island a few years later, the crocodile Cassius has lived at the Marineland Crocodile Park for over 35 years.

Estimated to have lived at least 110 years, some experts have said Cassius could be as old as 120, which would push the known limits of crocodile longevity.

What makes Cassius so unusual is that he has continued to grow despite his remarkable age: During an annual checkup this year, Professor Graeme Webb determined that Cassius had grown another 13 inches since his previous visit nearly 20 years earlier, now measuring a whopping 17 feet and 11.75 inches.

“He was a big old gnarly crocodile then… crocs of that size are not normal,” Webb told MIX 102.3 in Australia, saying that growing at such an advanced age “is unusual for a big croc.” 

Webb had determined during his first visit that Cassius was at between 30 and 80 years old, which would mean he could be at least 120, though there is no way to fully determine the croc’s age – especially given his unusual size and growth.

Marineland told Fox News Digital that the annual assessment is “very hands off” as the use of restraints can cause stress due to a heightened fight or flight response common to apex predators.

That stress can induce extreme trauma that could take considerable time from which to recover.

“Generally these assessments are done through observation in person and by looking at observation records kept by the keepers,” Marineland noted, citing such measures as stool and water samples for more detailed analysis.

The recent assessment for Cassius found him “fine with no immediate cause for concern, and no reason to believe Cassius will not live for years to come.” 

Marineland’s founder George Craig often likes to personally feed Cassius and has a “wonderful relationship” with the croc, according to Isberg. 

The oldest crocodile on record was a croc known as Freshie, who made it to 140 in captivity despite being shot twice in the tail and left eye, according to Oldest.org.