When Cassius — the world’s largest captive crocodile — died in Australia, his keepers thought he could be over 120 years old. Now, a necropsy could reveal his true age.
Investigation Underway to Determine the Age of Cassius, the World’s Largest Captive Crocodile
Cassius, the largest living captive crocodile in the world, recently passed away in Australia after spending 40 years in captivity. While experts estimated that this impressive saltwater crocodile (Crocodylus porosus) could be over 120 years old, a definitive age has yet to be determined. A necropsy and subsequent analysis of his bones may provide the answers.
Cause of Death and Age Estimation
Sally Isberg, founder of the Centre for Crocodile Research in Australia’s Northern Territory, indicated that all signs suggest Cassius died of old age. However, the autopsy may yield further insights into his exact age—something even his keepers had only guessed at.
When Cassius was captured from the Finniss River near Darwin in 1984, researchers speculated he might have been around 80 years old. Determining the age of crocodiles is complicated because, after they reach maturity, their growth rates slow significantly, making it challenging to gauge their age accurately. As Toody Scott, one of Cassius’ keepers at Marineland Crocodile Park, explained, “There is no way of knowing Cassius’ actual age as he was born in the wild, and the age is just an estimate.”
The Necropsy Process
To uncover Cassius’ true age, scientists plan to examine his bones post-mortem. They will cut into the crocodile’s back and right femur to extract samples, which will then be sent to a laboratory for analysis. “My plan is to send it to a lab that can cross-section it and look for growth rings, just like in trees,” Isberg told ABC News. However, she cautioned that the process could take months and may not guarantee clear results.
Grahame Webb, a zoologist who played a key role in Cassius’ capture, noted that counting growth rings might not yield an accurate age estimate. He explained, “These animals stop growing, and they can live for decades afterwards without growing,” making it difficult to determine age solely based on growth rings.
Cassius’ Impressive Size
At the time of his death, Cassius measured just under 18 feet (5.5 meters) long, but he had sustained injuries that resulted in the loss of part of his snout and tail. Webb believes that without these injuries, Cassius might have reached a total length of 19 feet (5.8 meters), further underscoring his status as a record-breaking predator.
As the necropsy results are awaited, Cassius’ legacy continues, highlighting both the remarkable lifespan of crocodiles and the challenges researchers face in studying these ancient reptiles.