Our Little Frogy is Hiding and Yes It is!

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Have you ever wondered why frogs are green in colour or brown or even a mix of these colours, and why does their skin always have to be slimy?

Well the answer is quite straight forward. These colours are used as a protective characteristic in camouflaging the animal in its natural surroundings. Though our little pet does not have to worry about predators, this camouflaging behavior is a defensive attribute that has been adopted by all, if not most frogs. To some extent they do have the capability to change their skin colour. This is done by expanding or contracting the pigment cells in the skin, thus making the frog look darker or lighter.

On the second part regarding its skin, why does it have to be slimy? Well frogs don’t drink water. They absorb water through their skin. Frogs are slimy because their skin is covered in a layer of mucus. This mucus helps the skin retain moisture thus hydrating our little buddy at all times. Frogs also use their skin to breathe as its skin is permeable to water and air. Also, their slimy skin functions as another defensive attribute, where it makes the frog slippery thus easily able to escape from predators.

Application in Biomimicry 

Although camouflaging is not a specific characteristic that is observed only from frogs, but this observation has triggered me on this idea. Armed forces around the globe have used this idea as a war tactic in battlefields. The uniform, military equipment as well as their heavy vehicles are as the same colour of the environment. this makes it difficult for them to be spotted by their enemies. 

The slimy skin of frogs would not make an attractive feature in engineering design, however its behavior as a membrane that allows water and air to diffuse makes it very much interesting to apply. Semi-permeable membranes such as the reverse osmosis membrane as seen in the figure below are widely used in water purification which functions with the same concept of a frog skin.