Micro Evolution of the Fox (Vulpes) | Creation Today

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Micro Evolution of the Fox (Vulpes)

How did we get so many different fox species? Does the fox (Vulpes) share a common ancestor with wolves, coyotes or jackals (Canis)? What exactly is a fox?

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Due to the complexity of this topic, this article will only deal with the genus Vulpes (true foxes).

NOTE: The gray fox, native to North America, belongs to the genus Urocyon and is not considered a ‘true fox’. Members of this genus are the only animals in the Canidae family that can climb trees, wherefore the gray fox is often referred to as the tree fox.

Variations within the genus Vulpes

There are many different species within the genus Vulpes and together they inhabit nearly all regions of the earth. This article will illustrate their variations, explain why those specific variations occur and what effect the environment had and still has on the process of speciation. I will introduce you to the following four fox species.

  • Arctic fox (Vulpes lagopus)
  • Red fox (Vulpes vulpes)
  • Swift fox (Vulpes velox)
  • Fennec fox (Vulpes zerda)

Those four species of Vulpes are very distinct from another and effectively demonstrate the factors behind the process of ‘micro evolution’.

NOTE: The term ‘micro evolution’ may lead you to think of one animal evolving into another. It is crucial to know that the process of ‘micro evolution’ is nothing else than adaptation or speciation within a ‘kind of animal’. This process is absolutely scientific, but unfortunately often confused with the unscientific theory of ‘macro evolution’.

There are generally three very important ecogeographical rules that apply when it comes to the variation within a genus: Allen’s rule, Bergmann’s rule and Gloger’s rule. I will focus on Allen’s rule and Bergmann’s rule to analyze the speciation within the ‘true foxes’.

1. Allen’s rule: This rule, discovered by Joel Asaph Allen (1877), states that animals adapted to cold weather generally (some exceptions) have shorter limbs than their relatives adapted to warmer weather. Homeothermic animals adapted to warm weather have low volume-to-surface ratios, while those adapted to colder weather have high volume-to-surface ratios. This simply means that animals living in a cold climate region tend to have shorter limbs (ears, tail, legs) relative to body size than animals of the same genus living in a warmer region. Long limbs emit more body heat which is a big disadvantage in colder climates, but a great advantage in warmer ones.

2. Bergmann’s rule: This rule was discovered by german biologist and zoologist Carl Bergmann (1847). It states that animals living in a colder region tend to generally (some exceptions) be larger than their relative inhabiting warmer regions. This rule was formulated in terms of species within a genus but also applies to a genus in general or a population within a species. It might even be possible that this rule applies to certain plants. The idea of this rule is that a larger body size saves more body heat than a smaller one, which is a big advantage for animals adapted to cold weather, but a disadvantage to those adapted to warm weather.

These ecogeographical rules have (at least to some degree) governed the process of ‘micro evolution’ (speciation) within the genus Vulpes.

1. Arctic fox

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This fluffy fox species inhabits the northern tundra regions of our planet and, to some extent, the boreal forests of northern Canada. Its body length ranges from 46 to 68 cm (18 to 27 in) and its tail length is about 30 cm (12 in). The ears and legs are relatively short and it has a generally rounded body shape to minimize the escape of body heat.

2. Red fox

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The famous red fox inhabits nearly all of the northern hemisphere from just below the arctic circle to northern Africa. It has even been introduced to Australia. It is fair to say that this fox species is well adapted to a wide range of climate regions. Its body length ranges from 45 to 90 cm (18 to 35 in) and its tail length ranges from 30 to 55.5 cm (12 to 22 in). The ears of the red fox measure 7.7 to 12.5 cm (3 to 5 in) and are quite larger than the ear of the Arctic fox. The Red fox is the largest of all fox species.

3. Swift fox

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The slim Swift fox inhabits the semi-arid prairie regions of Canada and the USA. It has a body length of 38 to 53 cm (15 to 21 in) and a tail length of 18 to 26 cm (7 to 10 in). This Vulpes species is relatively slim and has noticeably long ears. The Swift fox is the smallest North American member of the Canidea family.

4. Fennec fox

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This small Vulpes species is native to northern Africa. It can be primarily found running around in the sand dunes of the Sahara desert, where it also builds its den. It is the smallest member of the Canidae family and merely has a body length of 24 to 41 cm (9 to 16 in). Its tail is relatively long with a length of 18 to 31 cm (7 to 12 in). This fox is also very slim and has unusually long ears that can reach a length of up to 15 cm (6 in).

It is safe to assume that all those foxes had a common ancestor that lived in the days of Noah. In the course of thousands (not millions) of years the ‘ancient fox’ probably spread across the globe and through natural selection adapted to its environment. Allen’s rule clearly applies to the ear length of the four mentioned Vulpes species. The Arctic fox has the shortest ears while the Fennec fox has the longest. The Swift fox also has longer ears than the Arctic and Red fox, for its range is bound to a semi-arid region with relatively hot summers. The rule can also be observed when looking at the relatively long tail of the Fennec fox, which can even reach the length of its body. Bergmann’s rule also applies here, apart from the fact that the Red fox is larger than the Arctic fox. Especially the small Fennec fox is a good example of this. Further, the wide range of the body length of the Red fox is just a sign of its great adaptation to a variety of climate regions around the world.

NOTE: Natural selection isn’t the same as evolution (macro evolution).

Natural selection is an observable process in which organisms with certain characteristics survive better in a given environment. And there is a loss of information in the DNA. Genetic information decreases as a result of this process. Dr. Georgia Purdom (Ph.D. Molecular Genetics)

The process of ‘macro evolution’ requires a lot of information being added. For more on this topic check out: Is Natural Selection the Same Thing as Evolution?, by Dr. Georgia Purdom, Answers in Genesis, January 3, 2008

 

Do Foxes and Wolves Have a Common Ancestor?

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It is very difficult to say if those two animals have a common ancestor. There are many noticeable features that both animals share, and they are both members of the Canidae family, so one might assume that they must have had a common ancestor. Let’s look at the Bible!

And God said, Let the earth bring forth the living creature after his kind, cattle and creeping thing, and beast of the earth after his kind: and it was so. (Genesis 1:24 KJV)

Can a fox breed with a wolf or with any other member of the genus Canis? NO! Hybrids between a fox and a wolf, coyote or domestic dog are impossible due to the different number of chromosomes. The Gray wolf for example has 78 chromosomes, while the Red fox merely has 38 chromosomes, and the Fennec fox has 64 chromosomes. Does that mean that they haven’t been able to reproduce in the past? NO! It is possible that they used to be able to breed, which would mean that the fox lost genetic information (natural selection). Members of the genus Canis might have been able to breed with foxes in the past, just as the Fennec fox probably was once able to breed with his close relative, the Red fox. Putting that aside, the fact is that we don’t know it for certain and we probably never will. We weren’t on Noah’s ark to observe it.

It is important to note that one account from 1886 states that a captive fox bred with a female dog in Hanover Zoological Gardens in Germany. They had four puppies of which three died within the first few days. Although this account is highly controversial and doubted by many scientists today, it might have actually been possible just 150 years ago. This would serve as great evidence for the creationist and show that the large amount of ‘speciation within a kind’ on our planet was possible to occur in the course of only 4400 years.

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Kristopher Tribe (The Creation Guy)

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