Mrs. Brechbuhler of Brooklyn had picked up a packet of lettuce at the store and left it in the refrigerator. Three days later when she was putting together the salad, a lettuce leaf jumped, scaring the woman off completely. It took her a couple of minutes to realise that the green thing wasn’t a piece of lettuce. It was a perfectly matched frog about the size of her thumb! Mrs B and her daughter rescued the cold stowaway, named it “curious” and handed it to a reptile facility where it has been put up for sale as pet.
It is ironical that animal camouflage, which nature designed as a protection device, had almost taken the little frog to the brink of death!
In nature, the aim of every species is to find food and to not become someone else’s food. One of the most widespread adaptations towards these is an animal's ability to hide itself from predator and prey, through camouflage.
The simplest camouflage technique is for an animal to match the "background" of its surroundings. You can see this sort of camouflage everywhere. Deer, squirrels and many other animals have brownish, "earth tone" colours that match the brown of the trees and soil at the forest ground level. Sharks, dolphins and many other sea creatures have a greyish-blue colouring, which helps them blend in with the soft light underwater. The Arctic fox is very smart at this. In the spring and summer the fox has a dark coat, to match the brown dirt in its environment. In the fall and winter, it turns white, to match the surrounding snow!
Chameleons are the most popular example of animals that change colour. Most of the 100 types change from brown to green and back in just 20 seconds. But some turn almost any colour. Many people think chameleons change colour to blend in with their surroundings. But scientists say that light, temperature, and mood cause chameleons to change colour.
When a brown chameleon rests in the sun, it suddenly turns to green. This lighter colour helps the skin reflect bright sunlight. Similarly, if a chameleon is cold, it might turn a darker colour, because darker colours absorb more heat than light ones.
But mood causes the most spectacular colour changes. If a panther chameleon gets angry, red and yellow replace its normal colour. The animal's new look tells other chameleons, "I'm ready to fight!"
When a male wants to attract a female, he will wear his most flashy colours. One type of male chameleon will change from brown to purple and light blue. Even his eyelids turn yellow with green spots!
In addition to background-matching colouration, many animals have distinctive designs on their bodies that serve to conceal them. These designs might be spots, stripes or patches. For example, animals that inhabit areas with tall, vertical grass often have long, vertical stripes.
To us humans the black and white stripes of a zebra seem to make it stand out in a jungle. But to the colour blind lions, a herd of zebras doesn't look like a bunch of individual animals. It appears more like a big, striped mass.
The vertical stripes all seem to run together, making it hard for a lion to stalk and attack one specific zebra.
Many insects use mimicry to protect themselves. The back of the hawk moth caterpillar for example actually looks like a snake head!