Marineland Melanesia Crocodile Habitat founder and owner George Craig feeds Cassius. (Marineland Melanesia Crocodile Habitat)
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.
Cassius, the world's largest crocodile in captivity, could be 120 years old. (Marineland Melanesia Crocodile Habitat)
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."
