Colouration in Animals

Colouration in animals is determined by one factor, and that is not being seen. A prey animal wants to be able to hide from a predator so that it doesn’t become lunch, and a predator wants to be able to hide so that it can successfully catch its lunch. This “hiding” in form of colouration is also known as camouflage. 

Camouflage is used to avoid detection and it involves the skin, fur or feathers which incorporate the use of colours or patterns to blend in with the surroundings. As I said before, prey species use camouflage to aid their chances of survival by making it harder for predators to detect them. Predators use camouflage to avoid detection by prey to be able to hunt more successfully. 

There are four different types of camouflage and they are:

• Concealing colouration – this is where the body colour is the same as the environment, usually the vegetation or ground. This is the most common type of camouflage. For example, a lion Panthera leo. 
• Counter-shading – this is fairly similar to concealing colouration, but the back and belly are different colours. This is used for concealment from above or below. The dark ground matches the back when the animal is viewed from above. The belly is light coloured to match the sky when viewed from below. 
  • This type of shading can ‘flatten’ the animal, giving it a 2D appearance which makes it harder to see. A good example of a land animal with counter shading is an impala
  • This type of camouflage is fairly common in sea dwelling creatures.
• Disruptive colouration – this uses spots, stripes or other patterns. It is used to ‘break up’ the body outline so that it blends into the background. The overall shape is therefore disguised and appears all but invisible to other animals
  • Most mammals only have black and white vision, which relies on movement and shape.
  • Examples include kudu Tragelaphus strepsiceros, leopard Panthera pardus, bushbuck Tragelaphus scriptus, zebra Equus zebra zebra, E. z hartmannae, E. quagga and serval Leptailurus serval. There are many more examples all over the world, however these are just a few African examples for this type of camouflage. 
• Disguise – this can be easily confused with concealing colouration, however, as well as the colour of the animal blending in with the environment, the body shape is made to look like something non-living in its environment also. This is mostly used in insects, such as stick and leaf insects. 

So, as you can see, camouflage is very important to animals. But now let’s look at when colouration gets it wrong. Colour in animals is determined before the animal is born and is controlled by a gene. There are many thousands, maybe millions of genes that will determine how animals look and behave. It is the same in both you and me. We have two types of genes that will determine whether a specific trait is shown: dominant or recessive genes. A trait is the physical feature shown, such as hair or eye colour in humans. The specific trait genes are known as alleles.  Here are a couple of tables to show how recessive and dominant genes work:

	B	b
B	BB	Bb
b	Bb	bb

Both parents have brown eyes. B – dominant brown eye allele, b – recessive blue eye allele. BB – brown eyes, Bb – brown eyes, bb – blue eyes

So here in this basic diagram, it shows that both the parents have brown eyes but carry the blue eye gene. The dominant gene is brown eyes, however there is a ¼ chance that the child will have blue eyes. 

	b	b
B	Bb	Bb
b	bb	bb

One parent has blue eyes, the other has brown eyes. B – dominant brown eye allele, b – recessive blue eye allele, Bb – brown eyes, bb – blue eyes

The second table shows that one parent has brown eyes and the other parent has blue eyes. Brown remains the dominant gene, but as the parent with brown eyes still carries the blue eye gene, there is now a 2/4 chance that the child will have blue eyes.

Now back to discussing colouration in animals; there is an abnormality in animals which is caused by a recessive gene. The gene affected is responsible for the amount of melanin that is produced. Melanin determines how much dark pigment is produced and a defect to this can cause animals to be significantly lighter or darker than usual. Too much melanin will cause the animal to be dark and is called ‘melanistic’ colouring. A common example of this is a black jaguar Panthera once (which is often referred to as a black panther). Too little melanin causes a very light (often white) colouration of the animal, and it is termed ‘leucistic’. A good example of this would be white lions Panthera leo or tigers Panthera tigris. Both of these colourations can make it very difficult for animals to blend into their surroundings and in the wild they often won’t survive their infancy as it’s a lot easier for predators to find them. This then means that over time, through natural selection, the abnormal “recessive” gene trait will die out. However, there is an example in the wild of animals showing an abnormal colouration and surviving. These are the white lions of the Timbavati Region in Kruger National Park, South Africa. http://timbavati.krugerpark.co.za/Timbavati_Travel_Guide-travel/timbavati-wildlife.html Click or copy this link to read about the white lions of the Timbavati. 

It’s easy to confuse Leucistic animals with albino animals, but they are in fact different. The leucistic trait only affects the colour of the fur. Albinism affects the pigment of the eyes as well as the fur, such that Albino animals will usually have red eyes or very pale irises. 

Information resources:

• https://www.yourgenome.org/facts/what-are-dominant-and-recessive-alleles
• https://www.sciencedaily.com/terms/albinism.htm
• Carnaby. T. 2018. Beat About The Bush Exploring The Wild. 
• Carnaby. T. 2018. Beat about The Bush Mammals. 
• Apps. P. 2012. Smithers’ Mammals of Southern Africa

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