From MSNBC:
Researchers have followed up on Rudyard Kipling's classic tale to investigate why some leopards got their spots — and why others are spotless. In one of his “Just-So Stories,” Kipling suggested that the leopard scrounged up his distinctive rosettes because he had to stalk his prey undetected in a “great forest, 'sclusively full of trees and bushes and stripy, speckly, patchy-blatchy shadows.” Biologists think Kipling wasn't far wrong: The leopard-spot camouflage helps the cats move stealthily through the shadowed forest. But why aren't all big cats spotted? Researchers at the University of Bristol have developed a mathematical model that links the patterning of the leopard and 34 other species of wild cats to their different habitats. A paper about their research is being published in the Proceedings of the Royal Society B.
The model suggests that cats living in the trees within dense habitats, with high activity at low light levels, are the most likely to have complex color patterns in their fur. The cats that spent their time in well-lit and uniform environments, such as plains and grasslands, were more likely to have small spots or plain coats. The analysis supports the view that different patterns of camouflage reflect adaptation to different environments — and it also suggests that those patterns can change relatively quickly.
More here.