Why the Leopard Got Its Spots : Discovery News
The patterns and colors of wild cats' coats evolved as a means of camouflage in specific environment
Cat coat patterns and colors evolved to camouflage wild cats, according to a new study.
The behavior and habitat of cats help to determine the appearance of their coats.
Domesticated cats retain the genes that their wild ancestors had to control coat appearance.
From spots to splotches to stripes, cat coat patterns and colors all evolved to camouflage wild cats in their particular environments, according to a new study that finally answers the question: Why did the leopard get its spots?
British writer Rudyard Kipling, who posed and answered the question in a short story, turns out to have provided a partially correct explanation.
"Kipling was wrong to say that the leopard changed out of a plain coat and into a spotted one because it was forced off the High Veldt by human hunters. But he was spot on to suggest that environments 'full of trees and bushes and stripy, speckly, patchy-blatchy shadows' cause patterns like those of the leopard to evolve regularly," lead author William Allen told Discovery News.
Allen, a researcher in the Department of Experimental Psychology at the University of Bristol, and his colleagues made the determination after collecting images from the Internet of 37 wild cats.
Rectangular crops of selected images were taken to focus on coat patterns. Data from the images, along with information concerning the size of each species, its habitat, characteristic behaviors and more, was then plugged into a mathematical model of pattern development.
The model, outlined in the latest Proceedings of the Royal Society B journal, determined that spotted cats and cats with irregular coat patterns, such as leopards and jaguars, live in dense environments like tropical rainforests.
"Spots are also more common in species that spend greater amounts of time moving in trees, and in those that are active at lower light levels," said Allen.
Dark-colored coats, which are common to leopards and jaguars but unknown to cheetahs, were tied to species that may roam both day and night and that occupy a wide variety of habitats. Solid-colored coats were linked to cats that are active during the day, usually walk on the ground and that live in open habitats, such as in deserts or on the plains.
Stripes, on the other hand, remain somewhat of a mystery.
"There aren't enough species of stripy cat to reliably make associations between stripes and potential drivers of stripyness," Allen explained.
The study additionally highlights a few anomalies. The bay cat and the flat-headed cat, for example, have plain coats despite a preference for closed environments, but the researchers still believe that all cat coat colors evolved to camouflage these predatory animals.
Even domesticated house kitties sport evidence of their past wild heritage.
"Domestic cats have inherited the genetic architecture that enables them to express patterns seen on wild cats," he said. "A tabby would probably be better camouflaged in closed environments than a plain cat, which in turn would be better in open environments."
The appearance of feline fur does not precisely mirror the surrounding foliage and landscape of the animals, so the researchers suspect that a number of different factors promote camouflaged cat coats.
For example, "the patterns of dappled light and shade in forests seem remarkably similar to the patterns of many of the cats that live in these habitats," Allen said.
Marc Thery of the Department of Ecology and Biodiversity Management at France's National Museum of Natural History told Discovery News that he supports the new findings.
"I fully agree with the conclusions of the paper, and more particularly that felid's flank patterns are matching the visual properties of their respective environments to achieve background matching camouflage, and are also well adapted to their behavior," Thery said.
Allen is already busy at work on his next study: a look at color and pattern on snakes and on certain mammals, such as giraffes, goats and sheep.