DALS WILDLIFE SITE { WILDLIFE OF NORTHERN ENGLAND}

WILDLIFE OF NORTHERN ENGLAND

Teaching children about nature--1--MAMMAL COLOURATION. This is the first of a series of pages that will help children to have a better understanding of nature. I hope will will also inspire teachers to use it for that purpose. 

Have you ever wondered about the colouration of wild mammals, and what part it plays in its importance?. This is usually more than is generally realised. Illustrations of this can be notable even among the species that occur here in the UK. This colouration is, as one might expect, of more important in some species than others. It is prudent at this point to define the difference of coloration and colour. Colouration means the general affect of contrasting colours when present the effect of produced by the pattern of the coat.

As a rule the colouration of mammals and birds blend in with their environs. They harmonise with the ground or vegetation they are camouflaged . Thus the animal is capable of concealment in order to escape the prying eyes of predators, or to procure prey by creeping up upon them unawares.

The purpose is two fold in this instance for protection and ' aggressive'  purposes according as they serve as offensive or defensive purposes. It well be observed that the upper part of the body is much darker in colour than the under parts. The reason nature has designed this colouration is that the darker upper parts, being exposed to the light are rendered lighter as thus, much less conspicuous, while the lighter colour of the under parts cloaks the shadow which by the relation of the body to the ground is unavoidable.

These two actions have the general affect of breaking up the solid shape of the animal, so that it is afforded a certain degree of invisibility, which is amazingly effective. This will be testified by anyone who has startled a hare or woodcock for example, you can almost tread upon them before they flee from their hiding place..

There are some notable and puzzling exceptions, however, these are native to distant countries and would only be encountered in the UK in Zoos or Safari Parks.  The unusual Ratel {Honey badger} Mellivore capensis may be used to demonstrate this point.

Honey badger Mellivor capensis

Photograph courtesy of Jaganath via Magnus Manske { Creative commons attribution share alike}

Mammals that buck the trend.

On the honey badger the upper surface of the body is a hoary grey colour, while the under surface is jet black and the two are divided by a white line. no one knows for sure why this should be so. However, it may be a defense colouring.

Take the Zebra for example, how conspicuous  the broad vertical stripes appear  in the confines of a zoo or Safari Park. However, in their natural habitat they play an important role. The Zebra is a defenceless animal always vulnerable to lion attacks. This is especially true at night, for the Zebra is a day feeder and the night is generally spent sleeping. In the absence of natural light, ie, the moon and stars, the silent darkness is sufficient security from a surprise attack. However, in strong moonlight it is difficult, one would imagine, to hide such a large bulk escaping detection.

In this situation the broad contrasting stripes afford an amazing camouflage. If the black stripes were more numerous the animal would be seen as a black mass. Conversely if the white stripes were more numerous it would still stand out but as a white mass. However, the proportion is so perfectly balanced that, even at close range, the body exactly matches their surroundings,as seen by moonlight.

The tiger too, benefits from a similar camouflage the orange and black stripes of this animal helping it to blend in with the reeds and stems amid which it creeps upon its prey, unnoticed , until it is to late. 

The conspicuous stripes of the Zebra afford it camouflage on the moonlit nights.

UK mammals

The hare and stoat, familiar creatures here in the UK, demonstrate equally striking examples of this colouration. There are in fact two species of hare in the UK, the common brown or European hare,Lepidus europaeus, widely distributed and the mountain hare L. timidus, which as its name siggests id found in the more northern hilly and mountainous districts.

During the summer months, both these creatures are brown a colour which closely resembles the terrains they inhabit. A defence colouration that affords concealment from their many foes, such as fox,hawk and stoat. thus the hares need concealment to enable them to rest or they would be continuously subjected to hassle. As soon as the animal is in motion it becomes conspicuous, but a moving animal has at least a chance to escape. besides no amount of colouration which is strikingly at odds with its environs would be of little use to any creature.

Similarly, the fox and stoat are protectively coloured, however, not as defensive but aggressive purposes. It is used as camouflage as they creep upon their unwary victims which they happen to encounter. However, in countries where the winter is long and severe, where snow lies for long periods, brown hares on the one hand and brown foxes and stoats on the other, would be extremely conspicuous.

In consequence the pursued and the pursuer have to adopt a white colouration. In the Scottish Highlands only one species of hare is found-the mountain hare, which accordingly turn white, as does the stoat with the exception of the black coloured tip of the tail.

In Ireland where the mountain hare occurs, no such transition occurs, because snow fall is relatively rare and seldom lies for long upon the ground. 

Animals in their white winter colouration.

Picture courtesy of BHL.

In yet more northern regions of Europe the same species of hare is found. Also the fox{ which is a different species to the British Fox} as well as the stoat turn white.

We have reviewed animal colouration that touches on Stripes and patches of colour. now we review the spots as another important element of animal colouration. The spots of the leopard and the jaguar enhance the camouflage which affords them almost total invisiblity in the jungle that they inhabit. The light spots of these animals blend in perfectly with the dappled sunlight in these locations, so much so that unwary victims are often within striking distance before they realise it.

Here in the UK, it is the deer that are adorned in this way during late spring and the summer months. although these are lost in autumn when the long winter coat is the better colouring for them. The reason nature has deemed this to be so, is that, among naked trees a spotted deer would become very conspicuous. Those deer that occur in tropical regions keep the spotted coat throughout the year.

The markings of animals that inhabit the wild state throughout the world are always more or less symmetrical, rarely forming irregular patches, as in domestic cattle for instance. There are of course exceptions to the rule, the Hyena has irregular markings for instance. However, the number of species that do do conform to the rule are very very few.

Another example of this non-conformity is the unusual mammal -the skunk, which occurs both in north and south America. This carnivorous animal is conspicuously marked and is in no way an animal of concealment. However, this animal is capable of squirting a body liquid spray which is most offensive and over powering aroma. No attacker would want to duplicate the experience of this spray. 

Thus this kind of colouration is known as 'warning' coloration and is far more effectual than being armed with teeth and claws alone. The skunk is put in much less danger or damage. It is true  that one or two skunks are killed by inexperienced animals, as for an example the wolf, however, the spray that is released as a result of such an attack would be remembered by the aggressor, and an attack by that aggressor on another skunk during its lifetime would be very unlikey to occur.

 

The red fox is very conspicuous during the winter when out in the open

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