Cassius the giant crocodile died from sepsis after 40-year-old dormant infection burst from ‘abscess,’ necropsy reveals

An autopsy revealed that Cassius, a 5.5 meter long captive crocodile who died last year in Australia at the age of approximately 120, succumbed to sepsis.
An infection resulting from an injury Cassius suffered in the wild more than 40 years ago burst from a fibrous covering and “engulfed” the saltwater crocodile (Crocodylus porosus), killing him suddenly, Sally Isbergthe chief executive of the Darwin Crocodile Research Center who led the review, told ABC News.
Cassius had localized fibrosis near his left lung that exploded last November, just months after Isberg. carried out a health check and concluded that the crocodile was “happy and healthy”. Just 17 days before Cassius’ death, Isberg visited him and found no signs of illness. There had been no warning of infection until the fibrosis ruptured, because the casing kept the infection carefully packaged and sealed, Isberg said.
The infection probably occurred when Cassius lost his left front leg as a young man, before being captured in the Northern Territory and taken into captivity in 1984.
“What we didn’t know was that the rib cage was also damaged in this injury,” Isberg said. “At autopsy, his left rib was distended compared to the right,” because it harbored fibrosis.
The fibrosis eventually broke out because Cassius was getting too old, Isberg explained. “It’s because cells break down, they’re not able to renew themselves,” she explained. “He [Cassius] could not continue [making] this fibrous envelope around this infection.

After the death of Cassius, Isberg a bone was removed from his thigh to estimate its age more precisely. Staff at Marineland Crocodile Park, where Cassius lived for 40 years until his death, celebrated Cassius’ 120th birthday in 2023 – but this age was a maximum estimate, given that the crocodile was between 30 and 80 years old when it was captured.
Isberg hoped the femur would show growth rings, but tests did not yield a definitive result because temperatures at Marineland Crocodile Park are very stable, she said. Growth rings on crocodile bones vary with fluctuations in metabolism, which depend in part on temperature.
Cassius has now been taxidermied and returned to the crocodile park for an exhibition which will open on Saturday December 12.





