In May 2008, rangers at Kruger stumbled across a horrifying sight in the Olifants Gorge. The gorge, normally a haven for giant Nile crocodiles, was littered with their corpses. Before long, more than 30 dead crocodiles were located, all of which bore no outward signs of injury. The rangers were perplexed as to how these extraordinarily resilient creatures could come to die en masse. Park authorities immediately launched an investigation into the mysterious deaths, led by ecologists Danie Pienaar and Dr Danny Govender, but no clues were forthcoming. However, after conducting post-mortems on some of the dead crocodiles, the team realised that a disease known as pansteatitis was behind the mass die-off. "When we first cut open these crocodiles we noticed this orange, really hard, really rubbery fat," Dr Govender recalls. Pansteatitis, which is more common in domestic cats, is caused by a combination of consuming too much rancid fat, and a lack of vitamin E. The condition causes fat to solidify, leaving infected creatures lethargic, heavy and unable to hunt, eat, or defend themselves. Meanwhile, the death toll in Olifants Gorge continued to rise. Soon, the rangers spotted a crocodile feeding on the corpse of one of its own kind. The crocs had turned to cannibalism, and the only method of preventing the disease from spreading in this way - and potentially into the land predators such as lions - was to remove all the corpses from the gorge. The intervention had an instant effect, and for several months no deaths were recorded. Before long, the team had another huge setback when pansteatitis appeared to return to the gorge. What was the cause of this affliction?