Camouflage gear is widely used in the armed forces and by many hunters. Many animal species have developed the technique to a very high degree to either escape predators or to hide from prey. Usually the idea is to blend into the surroundings so that you disappear. The problem is that movement destroys the perception and eyes are usually very sensitive to motion.
We are familiar with tiger stripes and zebra stripes. With tigers it makes sense in that we may not notice them lying in wait in the stripy shade of the forest, but what about zebras? Grasslands are not black and white, so although it might help in stands of dead brushwood, the herd would be clearly visible while munching their way across the plain.
A recent paper by Scott-Samuel et al from the U of Bristol (1) addresses the effect of black and white patterns on the perception of speed. Navies in both world wars had used patterns like these. The reasoning was based on the idea that the range, direction and speed of ships would be difficult to estimate. They used stripes and zig-zags. Hi-tech weaponry makes this idea redundant, but how does this relate to zebras?
The experiments of Scott-Samuel et al looked at the effect of black and white stripes, zig-zags and checks on the accuracy of speed estimation of a target. At high speeds the zig-zag and check patterns caused to speeds to be underestimated by almost 10%. Vertical stripes weren’t quite as good.
So, back to our zebras. If they were galloping full tilt, it might be easier to miss with a rifle shot because of their stripes. Our lions, though, are a bit more hi-tech than the hunter with his gun and can turn and home in. However, it would be confusing to pick the initial target out of a fast moving herd running in various directions. That after all is the main reason for living in a large herd – hoping that someone else will be chosen to join the lions for dinner instead of you.
