Photo: Dusky’s Wonder
Most animals do have their own method of camouflage in some form or another. As we learned last week, mice in the desert have adapted to a sort of camouflage based solely on how dark or light their fur is. This ability to blend in with one’s surroundings can be as simple as the overall color of the animal, such as how white rabbits can hide in snowy environments and brown toads can hide in piles of leaves. I find this ability to be really fascinating and admirable, even, because it requires the animals to be aware of their surroundings and of the dangers within their habitat, and to use this awareness to their advantage as best as they can. Different kinds of animals use different kinds of methods of disguise. Some animals know when and where they can blend in, some more advanced creatures can alter their appearance based on their surroundings, and some don’t hide at all and instead disguise themselves as something dangerous or uninteresting.
The most basic form of camouflage is a coloration that matches an animal’s surroundings. After reading up on the subject a bit, I found that there are two ways in which animals can produce different colors. The first way is through Biochromes, or natural pigments in the body. From what I understand, this works in the exact same way that any other colored object does; the chemical make up of these Biochromes causes certain color wavelengths to be absorbed and others to be reflected. The second way is through physical structures on the animal, which act like prisms, refracting and scattering visible light so that certain colors are reflected. Polar bears are an example of this, as their skin is black but their fur appears white because the hairs are translucent and reflect the color of the snow. Both of these traits are determined genetically.
Often, color isn’t the only thing that changes; squirrels have rough and uneven fur that resembles tree bark. Similarly, many insects have a smooth outer shell that blends in with leaves.
But as seasons change, many environments go through changes too, and there are some animals that have learned to adapt their disguises to their altering surroundings. During the spring and summer, the Arctic fox has a dark coat to match the color of the dirt. In the fall and winter, the fox has a white coat, to match the snow. I thought this was really interesting, considering that animals’ fur and feather is so similar to humans’ hair and fingernails. Fur is essentially dead tissue and isn’t something an animal has power over, but apparently there is some sort of hormonal shift that occurs as the seasons change that causes an animal’s fur to change also.
Reptiles and fish have it easier, in that sense, because their color is determined by Biochromes that exist within living cells. These are called chromataphores — and they are super cool. Each chromataphore contains a single pigment, and they are surrounded by a muscle that contracts and expands. When the muscle contracts, all the pigment floods to the surface, thus changing the color of the animal’s body.
Then there are animals that have distinctive patterns or body types to help conceal them or make them appear uninteresting. Zebras, for example, will often hide from lions in tall grass because their stripes help them blend in with the vertical pattern of the grass. Since lions are color blind, it doesn’t matter that the zebras and the grass are different colors. Stick bugs also rely on their body shape and pattern to hide from predators. Their name makes it pretty self-explanatory — they look like sticks and hide in trees.
I think it’s really interesting how different animals developed different methods of hiding, and that there are so many things that factor into these very unique traits of every animal. It really makes me wonder how long it takes for most animals to perfect those genetics and how long it takes for natural selection to really take effect on certain adaptations.
Bioventures 
This was a really interesting post! I’ve never really considered how many different ways there are for a creature to “camouflage” itself. It seems that most result from a need to survive or escape danger. As humans, we really don’t need a form of camouflage, as there are no massive beasts or birds of prey tracking us for meals. But in a way, we do camouflage ourselves at times. As you said, zebras don’t really change themselves – they use the environment to their advantage by hiding in the tall grasses. We make similar choices in the clothes we wear or locations we place ourselves.
I wonder how the ways in which species’ camouflages would change if forced to adapt to a new environment? Do the Biochromes only function in a particular ecosystem? Would a species accustomed to a specific biome be able to camouflage itself in a similar fashion somewhere else? Some species might have it easier, as they can physically change based on their surroundings. But with animals like the zebra, they rely on what’s around them. It’s scary to think about how dependent some organisms are on their environments, and how susceptible those environments are to change.