Walk through a patch of prairie or along a beach just below the tide line; hike through the sand and rocks of a desert wash or among giant rainforest trees. Even as a seasoned observer, you may not see much sign of animal life. The creatures around you will be most noticeable when they chirp, twitter, or twitch; when they abruptly dive into the underbrush; or when their wings flash during takeoff. As a general rule, animals tend to blend in, rather than stand out, merging into the hues and patterns of the background. Small insects and birds of the...

Some of the most unusual animals in the ocean live just below the surface in gigantic, entangled mats of free-floating kelp called sargassum. These creatures appear exactly like pieces of the intertwined stems, floating bladders, and fronds that make up their habitat. They look very little like their relatives from closer to shore. Drawn together by the convergence of ocean currents, this underwater forest covers a highly variable area, depending on time of year and prevailing winds. In some places, the forest is scattered in patches; in others, it is so thick it can slow sailing vessels. Sargassum forests are...

Many biological changes unfold before our eyes in real time. An octopus transforms the color and texture of its skin in a few seconds; a moth emerges from a cocoon over a couple of hours; a tadpole turns into a frog in a few weeks. But evolutionary change in most animals is a slower, more ponderous process. Small, chance events distributed over large populations unfold over generations, and the time span for change is determined primarily by the rate of reproduction. Only rarely does animal evolution occur so rapidly that it can be measured within a single human lifetime. The...

On a bitterly cold evening in 1914, Pablo Picasso walked with Gertrude Stein along the Boulevard Raspail in Paris when a convoy of military vehicles drove past. World War I was just in its opening phases. These trucks and artillery were the first examples that Picasso had seen of the new military camouflage, in which various colors were combined in swirling patterns to obscure the outlines of the vehicle. Picasso excitedly proclaimed that the patterns on the trucks were an example of cubism, the avant-garde art movement that he and Stein had helped to create.¹

Military equipment had traditionally been...

Richard feynman loved to teach through unconventional but accessible analogies. In one of his accounts of light and vision, the Nobel Prize–winning physicist proposed that we imagine a swimming pool on a hot summer day, with lots of people repeatedly jumping in, swimming about, and climbing out again. The waves produced by each swimmer spread out and bounce off the sides of the pool. They interact and intermingle, adding and subtracting to produce a choppy chaos all over the water surface. Suppose that there is an insect, perhaps something like a water strider, floating on the surface in a...

The evidence of our own eyes has historically been the benchmark for interpreting animal coloration. But our visual system is one of many variations on the theme of seeing. Not all animals see the world the way we do. In fact, how an animal’s colors appear to humans may be about the least important perspective, in the evolutionary scheme of things. Since coloration evolves in conformity with the perception of predators and prey, we should instead be asking how those animals see. Innes Cuthill put it succinctly, “When a bird and a human look at the sky, they really do...

Napoleon bonaparte invaded Egypt in 1798 with twenty-seven warships, one hundred cannons and siege guns, and thirty thousand seasoned French soldiers. But the young general was not simply out for conquest and glory. He expected a cultural exchange, bringing to Egypt the benefits of French scientific progress and returning to France with a narrative of the land, art, history, and customs of the ancient Middle East. So Napoleon brought with him a large group of scientists, artists, and engineers that constituted his corps de savants. Their task was to learn everything they could about Egyptian civilization, to teach the Egyptians...

What does the color of lizards and pocket mice have to do with dodos, giant flightless moas, and pygmy mammoths? Each is the result of evolutionary processes that occur when populations of animals are isolated. Some of the best places to study the effects of isolation are archipelagos, chains of islands such as Indonesia or the Galápagos Islands, which inspired Alfred Russel Wallace and Charles Darwin to independently formulate their theories of evolution by natural selection. Wallace spent eight formative years in the Malay Archipelago, which includes modern-day Indonesia, the Philippines, Singapore, Brunei, and eastern Malaysia. Darwin was directly inspired...

Along la rambla, the famous boulevard in Barcelona, painted actors pretend to be statues. They are quite believable, until the statue takes a drink or asks for a donation. If we can be fooled, how do other animals tell the difference between real and pretend?

Visual predators live in a world of deceit. Dedicated imitators, with their lives at stake, do practically anything to avoid detection. The elements of animal deceit include nearly every aspect of identity: how an animal looks, smells, sounds, and behaves. Does it look like a shrimp or a frond of seaweed? Is it a caterpillar...

In ian fleming’s short story “The Hildebrand Rarity,” James Bond is vacationing in the Seychelles Islands when he is given the task of collecting one of the world’s rarest fish. It has only been seen once before, so all Bond has to go on is a verbal description of a pink- and black-striped fish with sharp, spiny fins. As he swims along the reef, Agent 007 muses to himself, “When you are looking for one particular species under water, … you have to keep your brain and your eyes focused for that one individual pattern. The riot of colour and...

Along nebraska’s platte River, among the hundreds of thousands of sandhill cranes that arrive in early March, you might get lucky and see one or two endangered whooping cranes. The field guide describes how to separate the features of one species from those of the other: The gray plumage and smaller size of the sandhill crane distinguishes it from the white body and black wing tips of the adult whooping crane.¹

Identifying animals in the wild requires that the observer not be distracted by individual differences but focus instead on the attributes that unite members of the same species. The...

Natural selection shaves the odds, tipping the balance even slightly in favor of one set of traits over another. Concealing coloration does not need to make an animal immune from predation in order for it to be favored for survival. It just has to make the animal less likely to be detected—on the average and over the long run—than less camouflaged members of the same species. The benefits of concealing coloration are a shift in probability, a slight advantage in the game, so slight that it can be seen only when summed over lifetimes of predator encounters. From...