Why the leopard got its spots

Oct 20, 2010
Patterns like the leopards rosettes evolve in cats which use forest habitats. Credit: Copyright is Cai Priestley 2008

Why do leopards have rosette shaped markings but tigers have stripes? Rudyard Kipling suggested that it was because the leopard moved to an environment "full of trees and bushes and stripy, speckly, patchy-blatchy shadows" but is there any truth in this just-so story?

Researchers at the University of Bristol investigated the flank markings of 35 species of wild cats to understand what drives the evolution of such beautiful and intriguing variation. They captured detailed differences in the visual appearance of the cats by linking them to a mathematical model of pattern development.

They found that cats living in dense habitats, in the trees, and active at low light levels, are the most likely to be patterned, especially with particularly irregular or complex patterns. This suggests that detailed aspects of patterning evolve for camouflage. Analysis of the evolutionary history of the patterns shows they can evolve and disappear relatively quickly.

The research also explains why, for example, black leopards are common but black cheetahs unknown. Unlike cheetahs, leopards live in a wide range of habitats and have varied behavioural patterns. Having several environmental niches that different individuals of the species can exploit allows atypical colours and patterns to become stable within a population.

Although a clear link between environment and patterning was established, the study also highlighted some anomalies. For example, cheetahs have evolved or retained spotted patterns despite a strong preference for open habitats, while a number of cats, such as the bay cat and the flat-headed cat, have plain coats despite a preference for closed environments. Why this should be remains unclear.

The study also highlighted just how few species of cats have vertical stripes. Of the 35 species examined, only tigers always had vertically elongated patterns and these patterns were not associated with a grassland habitat, as might be expected. However, tigers seem to be very well camouflaged so this raises the question why vertical stripes are not more common in cats and other mammals.

Will Allen of Bristol's School of Experimental Psychology, who led the research, said: "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."

Explore further: Bees able to spot which flowers offer best rewards before landing

More information: The research is published today in Proceedings of the Royal Society B.

Provided by University of Bristol

4.4 /5 (14 votes)

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User comments : 13

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kevinrtrs
1 / 5 (8) Oct 20, 2010
it wasn't the purpose to explain and so it doesn't explain HOW these stripes/spots and cat characteristics developed/originated in the first place. Hence the molecules-to-cat evolutionary story cannot be applied. But the researchers are of course using that sense and understanding of the word "evolution" in this case.

The information contained in the kind of animal known currently as "cat" was already put into place when they were created and so now it's simply a case of different genes being turned on or off to express those varying characteristic in the different animals we know - e.g. lion, cheetah, leopard etc.
No NEW information was gathered or created from mutations and natural selection - as Darwinian evolutionary thought would like us to understand. The information was already THERE.

Skeptic_Heretic
4.4 / 5 (7) Oct 20, 2010
No NEW information was gathered or created from mutations and natural selection - as Darwinian evolutionary thought would like us to understand. The information was already THERE.
If you knew anything about evolution and basic biological process, you'd understand why your statements are so idiotic.
JRDarby
3.7 / 5 (6) Oct 20, 2010
No NEW information was gathered or created from mutations and natural selection - as Darwinian evolutionary thought would like us to understand. The information was already THERE.


Tell me if you think new information was created here between the first permutation of the sentence and the second:

1. I helped my uncle Jack off a horse.
2. I helped my uncle jack off a horse.

The same information is contained in both. Nothing is new, really; the name just mutated away its capitalization. No information was created or lost, right? Yet the entire phrase suddenly took on a much different meaning...
BeckyW
not rated yet Oct 20, 2010
I have looked for the original paper in Proceedings of the Royal Society B (last 4 issues) and in PubMed. Can't find it anywhere. I found a reference to the doi on another news story, the doi doesn't exist. Is this a real paper? Please provide a link to it if it is. Thanks.
Donutz
4.3 / 5 (6) Oct 20, 2010
The information was already THERE.


the problem with this stance (that no new genetic info is ever created) is that new genetic info has been empirically observed any number of times within historical times. Since we've *seen* it happen, it *does* happen. You can hop from foot to foot and foam at the mouth all you want, you're not going to be able to make it didn't happen by wishing real hard.

trekgeek1
5 / 5 (1) Oct 20, 2010
I'm not exactly what you define information as. If we look at a byte of data, we have 8 bits. So I am assuming you would consider this 8 bits of information. If we added 8 more bits, I presume you'd acknowledge that we know have 16 bits of information. In genetics we frequently have gene duplication. The genes are duplicated and posses the same information as the originals. But we have increased the number of "bits" in the DNA. Doesn't this count as added information? If not, imagine that the replicated genes mutate and are now different from the original gene from which they were copied. Now we must conclude that information was added.
jsa09
5 / 5 (3) Oct 20, 2010
Not sure Kevin will get it no matter how many different ways it is explained.
Coldstatic
not rated yet Oct 21, 2010
No NEW information was gathered or created from mutations and natural selection - as Darwinian evolutionary thought would like us to understand. The information was already THERE.


Tell me if you think new information was created here between the first permutation of the sentence and the second:

1. I helped my uncle Jack off a horse.
2. I helped my uncle jack off a horse.



Did you not take high school english??? Removing the capital J means you have taken away the fact that its a proper noun. For example: You don't know jack. (ironically applicable)Compared to: You don't know Jack. The two sentences have completely different meanings. Just wanted to point that out.
Coldstatic
not rated yet Oct 21, 2010
This is in a seperate comment just incase it is removed. I helped my uncle jack off a horse. WAAAAAAAYYYYYYYYY different from I helped my Uncle Jack off a horse. Your arguing context that is all.
hylozoic
1 / 5 (2) Oct 21, 2010
"If you knew anything about evolution and basic biological process, you'd understand why your statements are so idiotic." -- ad hominum hubris.

"The same information is contained in both. Nothing is new, really; the name just mutated away its capitalization." -- Seriously? SERIOUSLY? Are you the obscure 'agent' Chance, now? Bwahahaha! Good one!
Coldstatic
not rated yet Oct 24, 2010
seriously though.... that poor poor horse
ultrasnow
5 / 5 (1) Oct 24, 2010
I hope horses can evolve so they need no help jacking off
Byagam_Gokulden
not rated yet Oct 24, 2010
In Soviet Russia horses jack off you