Cassius, the world's largest captive crocodile, has died in Australia after his health started declining in mid-October.
"It is with deep sadness that we share the passing of our beloved mate Cassius," Marineland Melanesia Crocodile Habitat & Gift Shop wrote in a Facebook post announcing his death. "He was more than just a Crocodile, he was a cherished member of our family and brought joy and companionship to his best mate George for over 37 years."
The saltwater crocodile (Crocodylus porosus) — who was 17 feet and 11.75 inches (5.48 meters) long — received the Guinness World Record as the largest living captive crocodile in 2011. But, as no one measured him since, he could have grown even bigger. The species can grow up to 23 ft (7 m) long.
Cassius had lived at Marineland Melanesia Crocodile Habitat on Australia's Green Island since 1987. He was captured in the Finniss River, near Darwin, in 1984 because he was acting aggressively and causing problems.
"As an apex predator, this big crocodile was getting into all sorts of trouble, from catching and eating cattle to attacking boat propellers," Marineland Melanesia's representatives wrote on its website. "It is believed this is where and how he sustained his many battle scars, including losing his front left leg, part of his snout and around 15 cm [6 in] off the end of his tail."
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Cassius was moved to an "assisted care residence" in Cairns on Oct. 5 and his health started declining shortly after. He died on Nov. 2. "He was very old and believed to be living beyond the years of a wild croc," according to Marineland Melanesia's post.
Although experts aren't sure, they think this massive croc may have been over 120 years old when he died. When he was caught, Cassius was estimated to be between 30 and 80 years old. Crocodile growth rates slow significantly once they reach adulthood.
"There is no way of knowing Cassius' actual age as he was born in the wild and the age is just an estimate," Toody Scott, one of Cassius' keepers at Marineland Crocodile Park, previously told Live Science, adding that his birthday "was essentially made up."
Despite his enormous size, Cassius wasn't the largest crocodile ever kept in captivity. This record goes to a saltwater crocodile named Lolong, who was caught in the Philippines in September 2011, and measured over 20 ft (6.17 m) before his death in 2013.
