Since the modern dog comes in many shapes, sizes, colors, and coat types, it’s amazing to think that all of these breeds fall under the same category: canine. From the Miniature Poodle to the Kerry Blue Terrier and the Rhodesian Ridgeback to the Scottish Deerhound, their coat colors, textures, and sizes may change, but all of these pooches indeed belong to only one species, the dog. The truth is modern dog breeds often have more differences than similarities which leads to the question many wonder about—are all dogs from the same species?
How Do Scientists Determine Which Creatures Belong to Which Species?
When determining which animals belong to which species, scientists base their opinions on the creatures’ genetic material, searching for genes and characteristics that meet a unique set of criteria. However, classifying breeds of dogs can be especially difficult since their physical appearances can differ dramatically. Even dog teeth vary so much in size that it can pose a challenge for a researcher to see that they belong to the same species since they can differ greatly from dog breed to dog breed.
How can this be?
Over time, man has refined the modern dog from its wild origins as the wolf into a domesticated companion with the traits it needs to fulfill its role in society and as a family companion. These selective breeding processes created a wide variety of breeds with many differing not only by their appearance and abilities but also by their geographical region.
Still, though outwardly, many dog breeds appear dramatically different; their genetic material is essentially the same. It is on the basis of these genes that we know that all dog breeds are indeed the same species and also are descended from the same ancestor: the wolf.
What Other Animals are Considered the Same Species as the Dog?
Technically speaking, the gray wolf is also classified under the same species as the domesticated dog. These two animals share a wide number of the same genetic materials, making them related to one another. However, many scientists argue that there are enough differences between the two animals that a subclassification should be included, making the dog “canis lupus familiaris” which indicates a relationship between the two, but that the dog is its own unique species entirely.
Though the gray wolf and the dog have much in common, there are some genetic variations. These variants are known as alleles. One of the main differences between the gray wolf and the dog is the 1GF1 gene that is responsible for the dog’s typically smaller stature and girth. This gene does not exist in wolves at all.
Do We Have Any Proof that All Dog Breeds are the Same Species?
Throughout history, reproduction has only been possible within a species, and thus, a cat cannot produce offspring with a dog or a lion with a giraffe and so on and so forth. A dog of any breed can be bred to a dog of another and the end result will be a litter of puppies. Though conventional wisdom advises against it; in theory, a Chihuahua could be bred to an Irish Wolfhound successfully.However, it is important to note the modern dog could also mate with a wolf and produce a litter of puppies, another indication that these two animals truly belong to the same species.
The gray wolf does have some unique characteristics to their body that dogs do not share. Dogs tend to have a very distinct, easily recognizable forehead that rests higher on the top of the skull than their wolf counterparts. Their muzzles are decidedly shorter than the wolf as well creating a more crowded environment for teeth in the mouth.
DNA indicates that the gray wolf and the dog are too similar to ignore, making a strong case for them remaining as a singular species. However, behaviorally, there are dramatic differences between the two.
How Did the System of Determining Species Develop?
There are two primary scientists who have been given credit for developing the series of classifying species: Carl Linnaeus and Charles Darwin. It was Mr. Linnaeus who first undertook this monumental task. He began by itemizing out a system for dividing animals into categories based on the qualities they shared in common. To help keep each group distinct, Mr. Linnaeus implemented the use of two different classifications as a means of identification: genus and species.
Working from the foundation Mr. Linnaeus lay, Mr. Darwin was then able to deduce an explanation as to how a species may have gone through a series of improvements to become a better, more sophisticated version of its original incarnation. This process was named natural selection and was responsible for identifying why some species prospered and others died out entirely. It is through the work of these two men that modern scientists are able to study and classify animals today.
What Steps are Involved in Classifying a Species?
The initial phase of classifying a species begins with an objective evaluation of an animal’s appearance. This observation allows the scientist to note similarities and differences that assist with determining which classification the animal is most suited to. However, using appearance alone to determine a species is nearly impossible to do since many animals can share similar or exact genetic material yet appear and act markedly different. As a result, a comparison of genetic material is also very important in this process.
Today, a new method of scientific evaluation is being developed. Its name is the Barcode of Life. This particular project aims to identify one specific genetic sequence that must be present in an animal in order for it to belong to a species. This commonality is referred to as that species’ bar code. This sequence of genes can vary some but only in a limited way in order for an animal to fall within that species. Today, a database exists that helps scientists in their efforts to record this sophisticated set of gene sequencing and the animals that fall within each species.
Are all dogs from the same species? Though their appearances may differ, their DNA tells the final tale: they are indeed!