What is the purpose of the patterning on giraffes? I assume either some sort of camouflage or for the purpose of attracting mates. Since (as far as I can tell) the males and the females look broadly similar I have to assume the former.
It’s very similar to that of cheetahs etc which rely on dappled shade to blur their outlines. But how is that working if they are so tall? Surely a single neutral colour like grey would help them blend in with the sky more. I can’t see how the patterning on a giraffe would help him blend in with anything unless he happens to be standing right under a tree. So what gives?
The pattern of giraffes is often given as an example of disruptive coloration, that is, coloration that breaks up the outline and makes an animal more difficult to pick out from the background. In my opinion this is unlikely. In my experience, they’re pretty damn easy to see; at least, they’re easier to see than an elephant. They are really too damn big to hide very effectively.
I think it is more likely for social reasons; not just for attracting mates, but to make individuals easily recognizable at a distance for herd interactions. The patterns are variable, making each individual in a group distinctive.
The spotted or striped patterns of cats are more likely to be for concealment, since cats can hide themselves in vegetation as they sneak up on prey.
The highly variable patterns of African Wild Dogs, on the other hand, are also probably for individual recognition. Unlike cats, these animals pursue their prey rather than ambush it, so camouflage is of limited value.
That’s sort of my thinking too. Hiding a giraffe is sorta like hiding an elephant and not easily done!
Do you have any links to evidence that it is about social patterning or was that just a guess? I know that zebra are thought to have highly individual stripe patterns. I wonder if giraffes are the same.
There’s plenty of references stating that the pattern of each individual is unique, such as this one. These distinct patterns are used by researchers for individual recognition, so there’s no doubt giraffes could do so too.
I am not aware of specific research on the role of patterning in social recognition; that’s just what seems to me to be the most likely function.
I think this is the likely explanation for zebras as well. Although the pattern is sometimes also attributed to disruptive coloration, under most lighting conditions they are pretty easy to see, and more so than if they were a solid color.
Dunno… while not as effective as the zebras’ camouflage… I think giraffeshave a pretty decent camo pattern, especially from a lion’s point of view. And if the lighting happens to cooperate… they’re pretty hard to spot.
I thought disruptive patterning was not so much about hiding as it was about confounding the visual system of the enemy - in the case of zebras, it can be particularly difficult to focus consistently on a chosen individual within a dense herd (singling out an individual is something a predator might want to do). It’s probably worth also remembering cheetahs and lions probably see and perceive things differently from the way we do, too, for several reasons.
Please do remember that some things don’t have to be “for” anything - they’re traits that showed up in some ancestor and were not sufficiently negative to be bred out of the species.
That said, when the entire species has the trait that seems less likely.
Well, remember that the distant ancestors of today’s giraffes were considerably smaller. It could be that the camouflage pattern was more useful in concealing those ancestors than it is in concealing today’s giraffes. In which case it’s a relic that doesn’t serve much purposes (though it could have a role in disruptive camouflage) and doesn’t harm the species so it has been retained.
I don’t find any of those convincing, especially if you compare them to a more subtle pattern. When I’ve seen giraffes in Africa, they’ve been pretty easy to pick out, even in woodland from a moving car.
And also, adult giraffes are so large they have virtually no predators. (Lions may take them, but it’s pretty rare.) Many ungulates, including deer and tapirs, have spotted patterns when they are young which are lost when they are older. Even if the pattern were for camouflage, you might expect adults to lose it when they became big enough to deter a lion.
This may be true in some cases, but is probably not true for disruptive coloration in predators like tigers and leopards where the pattern has to work mainly when the animal is still or moving slowly rather running rapidly. It may well be a factor for zebras, where there may be an element of predator confusion in a rapidly moving herd. However, Jonathan Kingdon, an expert on African mammals, proposed that stripes have a social function in zebras.
Obviously this can’t be the case for giraffes - they don’t occur in large enough herds for a predator to really get confused about which one to follow, and in any case the pattern is not the kind of “dazzling” one zebras have.
In dry open veld giraffe are easy to spot but in areas where the bush is taller and denser they can hide quite well. I have been through the Hluhluwe Imfolozi Park in kwaZulu-Natal on many occasions and was often surprised by quite large giraffe suddenly appearing out of the bush. On one memorable occasion we had stopped on a corner to look at something spotted in the distance only to have *three *of the buggers suddenly appear from behind some tall trees quite close to us. So in the right environment, less woodland and more giant vicious thorn bushes, giraffes can blend in quite well.
I saw on one of those BBC nature videos where they say the spots on giraffes along with the thick African air, cause the illusion of movement. This means even when the giraffe is standing still the rising air and the patterns will make it look like the giraffe is active, thus confusing the lions. Lions are pretty much the only animal capable of taking down a full grown giraffe.
While this is true as a general principle, when you have a feature as unique and flamboyant as the color pattern of the giraffe, it is entirely reasonable to ask how it might have come about. We do know that animal populations are subject to natural selection, and features like color pattern do often have obvious relationships to predation or social interactions. It is quite unlikely that a color pattern of this kind “just happened,” or that if it did it would be immune from natural selection.
Another line of evidence that the color pattern is more for the purpose of social recognition is the regional variation in color pattern in different parts of Africa. If the color pattern was for the purpose of camouflage and maintained by selection, one would expect it to either converge on a single pattern or vary fairly systematically depending on the kind of environment. Instead, it varies rather randomly. If the pattern is just so individuals can recognize each other, the exact kind of pattern doesn’t matter, and it can be expected to vary more randomly between populations.
This kind of variation is also evident between zebra species and populations, especially in the recently extinct quagga of southern Africa, closely related to the Plains Zebra but lacking most striping.