Some animals like to sport bright colors, as if they want to be seen. Others favor drab colors, as if they want to blend in and avoid recognition. There must be advantages to both strategies. Soldiers used to sport bright red clothing in the field, and now tend to go with grey and olive blotches, if they are in forest, and beige spotty patterns if they are on sand. The invisible hand of evolution is at work in the natural world and the visible one of tacticians is at work in the military one, both hands working on the vital competition of appearances. There aren't so many soldiers who are still trying to stand out, but the animals who do so, and plenty of soldiers and sailors and animals who try to blend in, all come under the attention of _Dazzled and Deceived: Mimicry and Camouflage_ (Yale University Press) by Peter Forbes. The effort toward understanding military and natural camouflage has been not just separate efforts by naturalists and soldiers, but combined work in the field, joined also by artists and even a magician. Just as you would suspect, there are plenty of surprises in this book, along with a fine introduction to the evolution of mimicry down to the current biochemical understandings.
Forbes spends much of the book on butterflies, like _Leptalis_, which use camouflage in a distinct way. They mimic the bright colors and patterns of another butterfly, the _Heliconidae_. What was the advantage of looking like another butterfly? The imitated _Heliconidae_ sported bright colors as a sort of warning; it wanted to be seen and recognized, because it tasted bad and was unpalatable. The more recognizable it was, the more often bird predators would leave it alone. But _Leptalis_, on the other hand, was tasty. It displayed the warning colors and markings of _Heliconidae_, but in the case of _Leptalis_, the warnings were false. False or true, the warnings helped give each butterfly a better chance of surviving and passing on its genes. The false imitation warnings were complicated enough (and occur in other species like snakes, not just insects), but there were true imitation warnings as well. Unrelated species of bad-tasting butterflies (and even moths) shared colors and markings. Their true warnings reinforced each other every time a bird tried to eat one and learned how bad a creature with such appearance tasted. In the 1890s, a cranky New England painter burst into the realm of naturalists who were concerned with camouflage and mimicry. Abbott H. Thayer thought that only an artist could rightly appreciate the profundity of the deceptive pictures made by birds and animals. He obsessively insisted that coloration was for no other purpose than to obscure the animal; he didn't accept that colors might be bright for the purpose of warning. He was dogmatic and pugnacious about his discoveries of coloration, and took it upon himself to advise the US Navy about how to disguise its ships during the Spanish-American War. His ideas were ignored, but he did patent the idea of countershading ships, and went on to design disruptive coloration for them. He teamed with the Scots zoologist John Graham Kerr to have British ships painted in "dazzle" patterns, bold darks and lights that obscured the form of the ship and even made it look as if it were on a different heading from its true one. The interplay between military tacticians, naturalists, and artists (which, given the personalities involved, was often angry) gives Forbes a background to tell a broad story about camouflage, including how tanks were hidden in the African campaign of World War Two, and how the flamboyant magician Jasper Maskelyne helped troops and equipment disappear (or was it all hocus-pocus?).
Much of Forbes's book describes the science and scientists working out how chromosomes have activated the chemistry that, for instance, turns inheritance into particular wing colors. There are good profiles of artists and scientists. It is a pleasure, for instance, to read about Miriam Rothschild, who was a member of the famous banking family, and used some of her fortune to equip a laboratory in her home where she investigated how inedible monarch butterflies got their toxins. She worked out how caterpillars evolved an invulnerability to toxins of particular milkweed plants, and not only did this make the plants their particular field of forage, they absorbed the toxins into their own systems to make them toxic in turn. She tested the toxins on starlings - the birds vomited. He explains how the animal most famous for blending in, the chameleon, actually is more likely to change its colors for the purpose of standing out, like for signaling aggressiveness between males. He writes admiringly of the best trickster in nature, the octopus, that "compendium of every camouflage and mimicry technique known." Ranging into art, military tactics, field biology, evolution, and biochemistry, Forbes has given a unique look into the hidden techniques of natural and artificial camouflage. Natural and artistic and military techniques, he shows, don't follow any particular advancement or grand design; they all in their fashion take their chances, make choices, and do experiments.