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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.
The findings would explain why black leopards (also known as black panthers) are common, while black cheetahs don't exist. As explained in a news release about the research, leopards live in a wide range of habitats ... and some of those habitats offer lighting conditions and behavioral patterns that would favor black leopards over spotted cats. Cheetahs, however, live in a more limited range of habitats.
The research does raise a few questions, however: The mathematical model generally associates spots with closed environment. But cheetahs are spotted even though they favor open environments, and the bay cat and the flat-headed cat have plain coats despite their preference for closed environments. Why doesn't the model hold true in those cases? (It could be that the cheetah is so fast it doesn't need to rely on camouflage.) And why is the tiger the only species among the 35 studied to have vertically elongated stripes?
One thing's for sure: The researchers aren't stopping with leopards. Like Kipling, they're gearing up to address other questions of coloration. For example, why do zebras have stripes? Some researchers have suggested that the zebra stripes aren't meant to serve as camouflage, but rather as a cooling system or an insect repellent. Mathematical modeling could provide further evidence for or against such hypotheses.
"The method we have developed offers insights into cat patterning at many levels of explanation, and we are now applying it to other groups of animals," the University of Bristol's Will Allen said in the news release.
More about animals and camouflage:
- New ways to hide a hunter
- Some sharks can become invisible
- Astonishing octopus is a master of disguise
- Lizards' camouflage reveals evolution in action
In addition to Allen, the authors of "Why the Leopard Got Its Spots: Relating Pattern Deveopment to Ecology in Felids" include Innes Cuthill, Nicholas Scott-Samuel and Roland Baddeley.
Connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. You can also check out "The Case for Pluto," Alan's book about the controversial dwarf planet and the search for new worlds.
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A common misconception about evolution is that all animals are 100% perfectly adapted to their environments. There are in fact always inherited traits that are either neutral (e.g. Gould's famous panda's thumb) or slightly harmful to the animal (but not harmful enough to wipe out the species in a generation).
The general trend for cats appears to be spots for closed environments are plain coats for open environments, but we can't expect evolution to produce those results exactly 100% of the time. There are too many variables.
The fact is that sometimes a trait or gene can become common in a gene pool for some random reason, such as a bottlenecking population or association with another gene that does confer an advantage.
Then I guess that "evolution" is not so efficient after all, is it? Kind of makes you wonder about the theory's validity...
Actually, evolution is pretty efficient. If all animals were 100% adapted to their current environment and incapable of adapting to any other conditions, God's creation would be far less magnificent than it in fact is. Very clever of God to come up with the idea of generating new life through sexual reproduction, which pretty much forms the basis of evolution and guarantees that it will occur.
Evolution is the antithesis of efficiency. It depends on chance and time on a scale that is longer than man can grasp, and it always ends up generating compromise after compromise to efficiency in the name of survivability. It works the same way as if you could have an infinite number of monkeys endlessly banging on the keys of a typewriter -- given enough time, one of them will type the bible word for word.
Grasslands are not a golf course, but dappled with highs and lows, brush and scruff. Cheetahs spots do provide camouflage for sleep, stillness, watchfulness. I enjoyed reading of the many "mutations" including the "King Cheetah" with three stripes down the back. It requires a recessive gene from both parents. [Wiki]. Cheetah also sports long tear markings.
How did the zebra earn its stripes? Is it more like a horse or a donkey? A jackass is a male donkey. A mule is a cross between a horse and a donkey. Zebra is perhaps not as stubborn and unwilling to cooperate as a donkey. Did you know that Mr. Ed (a horse, of course) was really a donkey? Story goes that it wasn't necessary to paint the donkey, since the old film didn't pickup on the stripes.
This does seem weird, but watching the 1906 film clip of San Francisco (60 minutes) from the street car view didn't reveal much in the way of pin-stripped suits or clothing patterns. It did document what was, just days before it no longer was, as the earthquake and fires took down what was built upon forever shaky foundations.
God's creatures are ALL guides for mankind. The late, great Ted Andrew's "Animal-Speak" and "Animal-Wise" should be in the hands of every reader. Why? Because your soul is trying to communicate with you the human animal and is desperate for every tool you are willing to USE, THAT'S WHY!
Mr. Ed a donkey? No way. Mr. Ed was a palomino horse.
I think you need to check your information, sugar. Mr. Ed was not a donkey he was a palomino horse. Donkeys are significantly smaller, have larger ears and a very different facial structure. If you had said mule, I would have thought MAYBE, but it is well documented that Ed was a palomino (blond for those not familiar with equines) horse. Zebras are more like donkeys in their independence and are way more difficult and stubborn to train than both a horse or a donkey, so I've been told by folks that work with Zebras on private ranches near me. Many people have cross-bred zebras with both horses (called a Zorse) and donkeys (called a Zedonk) and from all reviews these cross-bred animals continue to maintain the Zebra's streak of independence. Just a few fun facts for you to enjoy!
It has been theorized, with some logic, that the striping of zebras is a mechanism to prevent the predators from singling out one animal when the herd is moving, since the stripes make the whole herd appear as a single individual. If you look at zebras when they are standing or running in close formation, you can see how difficult it would be for the predator to pick out one animal.
my first thought was kiplings "just so stories" ...maybe NYC's fashion week has something to do with it...after all where would fashion be without the spots...
I thought zebra stripes were meant to confuse predators - when a bunch of zebras are together, it's hard to tell where one ends and the next begins, making it difficult for a predator to single one out.
That would seem to make sense to me as well, but some researchers have said the camouflage effect is not that big of a deal for the zebras. Nevertheless, the pattern is so crazy that you'd have to think it would confuse a predator.
Considering that the cats are colorblind, an endless sea of black and white stripes only adheres to the idea that it was strictly meant as a camouflage tactic. We could also go beyond cats and zebras, certain schools of fish are purposely dark on top and light on bottom, a bottom dwelling predator will find it hard to distinguish the fish from the light beaming down from the surface, while predators on top will find it hard to distinguish the dark tops from the darkness of the sea below.
I though the dark spots were dark to absorb more infrared radiation for body warmth.....shows what I know *L
duh
Haha I learned of their coloring in my Marine Biology class :)
One thing to consider about Cheetahs -
The entire existent population of cheetahs are not very genetically diverse. Darwinistic view is that cheetahs bred and selected for speed over nearly every other trait. This may have, over generations, removed less-spotted and non-spotted variations from the gene pool.
Perhaps this overselection of one trait can be blamed for the existence of plain-coated cats in closed environments as well as spotted cats in open environments. It takes a broad, robust gene pool to survive change to an environment if the single selected trait becomes less adaptive...
I think some cats just like the looks of spots and others do not....... ;)
Cats have always been may favorite predator, especially panthers. Such beautiful majestic beasts. Truly is sad how their habitats are slowly disappearing, them along with it.
The spots that survived are the ones we are associating with their habitats to explain their presence in these habitats... but others may have existed in these habitats but died out due to other reasons, not necessarily due to having (or not having spots). Anyway, felines are the most fascinating creatures on this planet, if they become extinct, I dont wanna exist either...
Now I can sleep.
I wonder if city dwellers have more tats and tat sleeves than suburban or rural inhabitants. If so, they might blend in better...
For this they needed a study???? Do these so called scientists ever spend time outdoors???? I have a grey cat that can hide perfectly in green grass....every time the dog is in sight!!!
Just goes to show God knows what he's doing!
Zebras have stripes to make the herd look like one large entity, making it harder for predators to single one out...it's a self preservation tatic utilized by the group. I'm pretty sure other research has already confirmed this....
They are just now spending money to research something my grade school teacher taught me back in the 70's? Camouflage has been an animal defense and predator's have been less noticable for thousands and thousands of decades.
A trillion dollars in national debt and people spend money on this useless already known theory. I've seen a lot of shows on wildlife that show Zebra's with flies and several other insects buzzing and flying around to know that their strips aren't insect repelent. Could I get the money for that grant to spend on something actually needed.
Read the story please. This research was done by the University of Bristol. As in Bristol, UK...so this doesn't involve USA money at all. I'm not really sure what Englands national debt is but i doubt you're really concerned about that anyway.
If you look close at a panther, it has spots too.
I thought Zebras have stripes to confuse lions who have poor eyesight. The stripes are a defense mechanism for Zebras and cause confusion to the lion who can't singal out an individual Zebra from the herd.
When the big bang occured. What was it that actually banged. Where did the nothingness that banged come from. And I always wanted to ask what happened to the species in between chimpanzees and humans. Why were (neanderthals) not smart enough to move on but chimps gorillas and baboons were? Someone who thinks they know it all really needs to help me.
The Big Gang is still a very raw theory. Scientist are still in debate about how everything started. Humans did not evolve from Chimps. Humans and Chimps share a common ancestor. No one knows why Neanderthals died off. It could have been from disease or anything.
Hmmm, interesting! So, in other words...it comes down to Vitamin D.
Vitamin D is the meaning of existence
Are zebras white with black stripes, or black with white stripes?
Neanders may not have "died off" so much as been killed off through social oppression in mixing with later homo sapien sapien after spreading out, as the Mayans seem to have spread out from their main compounds thereby causing an end to the purity of the gene pool altogether. Lack of adaptation is not a problem in as much as being reclassified from hunter to prey. In this regard, the only adaptation to make when becoming prey, is mixing the gene pool it self in order to mask traits and adopt differing traits. The human animal does this with much success!
Leopards have spots because God made them that way.