Australia’s Spectacular Jumping Crocodile Cruise was winding down the Adelaide River on Sunday when passengers spotted a crocodile that was quite spectacular indeed. As the BBC reports, the adult croc was not grey or green, but white—a rarity in the reptilian world.
Hypomelanism, or a reduced quantity of the pigment melanin, caused the animal’s snow-white skin. Adam Britton, a research associate at Charles Darwin University, tells the BBC that the condition is driven by genetics, or by excessive heat during the incubation period.
"During incubation, if the eggs in the nest get a little bit too hot, it can lead to errors in cell division and cause mutations," he says.
Britton tells the BBC that it is “not uncommon” for crocodiles to be born with hypomelanism. But because white crocs are more visible to predators, it is rare for them to reach adulthood.
The Northern Territory Conservation and Protection Society, an unofficial conservation group, has dubbed the Adelaide River crocodile “Pearl.” The animal “was hanging out in the territory of a large male which is a good indication it’s a girl,” the founder of the group, who asked to be identified only as “Broady,” tells Smithsonian.com. But since crocodiles’ sex organs are difficult to observe, experts would have to conduct an internal exam to be sure.
In a Facebook post, the NT Conservation and Protection Society suggests that Pearl is related to a famous Australian crocodile with a black body and a white head. That crocodile, which also lived in the Adelaide River, was shot in 2014, after it attacked and killed a 57-year-old man.
Broady, who was on the cruise when Pearl was spotted, said that she was overwhelmed by the sight of another white crocodile.
“[I] spent most of the day in tears,” she says, explaining that the emotion mainly stems from the thought that the new croc could be the famous creature's relative. “It’s wonderful to think a animal as majestic as him has [passed] on his genes and in a way lived on in the river.”