Which is better?
This is the question I’ve never been able to answer correctly when going shopping to buy a blouse or a jacket with my wife. If I’d say the spots look nice, she’d reply, but what about the stripes? If I then say the stripes look even better, I get to hear “but they make me look fat”. If I then suggest a patchy kind of pattern, I get told that I’m of no help. Can animal coat patterns help in cases like these? Let’s examine.
Dots and spots are surprisingly common amongst predatory animals and the leopard immediately comes to mind. Leopard, ocelot and jaguar need to approach their prey unseen and during the day in or under trees, the changing patterns of shaded and sunlit patches (caused by the movement of leaves and vegetation due to the wind) renders them almost invisible. Hunting at night under moonlight would undoubtedly make it even more difficult to see them. The cheetah is also spotted, but does not live in the jungle or amongst dense vegetation and hunts during the day. Why isn’t the cheetah sand-coloured like a lion. Hyenas also have spots, but often they don’t even hunt at all; they steal the food from others.
Not all cat predators with spots are big: some smaller ones like housecats and the Australian quoll have spots, too. But tigers always have stripes, mostly vertical ones that is. It certainly makes it more difficult to spot a tiger when it is prowling around in high grasses. It’s probably correct to say that dark and lighter spots or vertical stripes are a form of camouflage allowing a predator to approach its prey more easily. However, even prey may have spots or possess stripes. Fallow deer and, of course, bambis have spots, but the bovid species ‘bongo’ and the small antelope ‘zebra duiker’ possess vertical stripes just like zebras. The stripes of the latter, however, are not vertical on the legs but horizontal. Horizontal stripes along the body are typical of wild piglets and young tapirs, and even emu chicks, but would that help them to remain undetected? One should think that vertical stripes would be a better camouflage.
Snakes and lizards are long and slender and that is often amplified by horizontal lines along the body and tail. This would certainly make sense if there weren’t these crass exceptions: coral snakes and sea snakes are vertically striped, possessing red or yellow bands on a black background (or black stripes on a yellow or reddish background) which does not render them cryptic, but highly visible. But is it wise to be seen, to be recognized? I suppose if you are venomous and can defend yourself (and the attacker does not die, but would remember to leave that stripy fellow alone) it would be an explanation. To explain similar body colour patterns, Batesian and Müllerian mimicry come to mind. The skunk’s black and white coat has a similar message: ”I’m not an easy prey; don’t you remember that nasty lesson I taught you the last time you tried?” Most likely the immensely colourful spots and stripes of many tropical and venomous frogs and the black and yellow spots of salamanders are warning colorations too.
And under water? An enormous variety of colours, spots and stripes – but no single “unifying” rule. The most gigantic fish, the whale shark, has spots. But so have many puffer fishes and tiny box fishes, for example Ostracion cubicus. Freshwater fish like trout may have spots, but also some skates and the catfish Synodontis negrita, too. Another catfish, the slender Plotosus lineatus, has horizontal stripes, but many open water species and the cryptic moray eel Gymnomuraena zebra have vertical stripes. Many tropical angel fishes have horizontal stripes. Some cichlids and the lionfish Pterois sp. have both spots and stripes. And the reason for this piscine kaleidoscope: the flickering and constantly moving shady and lit patches created by the waves and the movement of the water above (plus the coral habitat, rocks and bottom substrate). Does this knowledge help our lady (see the beginning) to decide whether to choose the spots or the stripes? With clothes and women, you’ll never have a satisfactory answer.
© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2020.
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