Zoology

How and why Animals Developed Camouflage



Tweet
Ian's image for:
"How and why Animals Developed Camouflage"
Caption: 
Location: 
Image by: 
©  

There are two reasons for camouflage. The first is to avoid being seen by a predator that would eat you. The second is to avoid being seen by an animal you want to eat.
The animal that avoids detection by predators is likely to live longer, to breed and to pass his or her successful genes into the next generation. This also applies to the well-fed animal that uses camouflage to catch its prey.
With each new generation, the best camouflaged animals are the ones that survive. So their camouflage improves until it reaches the perfection of an orchid praying mantis that lives on pink and white flowers and is pink and white. It cannot be distinguished from the flower it lives on until it strikes. Too late for the victim.
But what if the scenary changes? Without its orchids, the orchid praying mantis would be clearly visible and would become dinner itself.
The UK's peppered moth is proof of the way the survival of the fittest - in this case the best camouflaged - works. The coloration of its wings used to be black peppering on white. On clean tree trunks its camouflage was perfect. Occasionally sports that had white peppering on black cropped up. These were spotted by birds and eaten, but the genetic possibility for these sports remained.
Then came the industrial revolution and the tree trunks slowly became grimier and grimier. White peppering on black wings became the better form of camouflage on dirty tree trunks. So the sports survived and the previously successful black-peppering-on-white moths gradually disappeared, eaten before they could breed.
Killer smogs so bad that thousands of people died forced the UK Government to bring in the Clean Air Act in the 1960's. Our tree trunks became cleaner and cleaner. Guess what? The peppered moth is reverting to its original coloration.
Camouflage usually takes millions of years of evolution to develop. In the case of the peppered moth, going from common form to sport and back again, this process took only a few hundred years. The moth was very fortunate to be so adaptable. Fortunate for us too, because we could see how the process works.
Note: the Imperial War Museum in London is currently running an exhibition on military camouflage. It adds a new perspective to our thoughts on evolution.

Tweet
More about this author: Ian

From Around the Web




ARTICLE SOURCES AND CITATIONS