Domestic dogs have some of the biggest size and appearance variances of any species in the world, with enormous specimens like Great Danes standing around 3 feet tall at the shoulder and weighing 200 pounds or more, while the diminutive Chihuahua is only about 6 inches tall and 5 pounds in weight. It truly beggars belief that these two creatures could be so closely related.
So, are Great Danes and Chihuahuas really the same species?
Great Danes and Chihuahuas are indeed the same species: Canis familiaris. Both breeds, like all domestic dogs, have 78 chromosomes arranged in 39 pairs, which means that they can (technically, if not necessarily naturally in practice) produce viable offspring. All dogs descended from wolves, with different breeds only arising from human intervention.
Let’s look more in-depth at how we can be sure that Great Danes and Chihuahuas are the same species.
How Are Species Distinguished?
There are three main ways that different species are distinguished:
Appearance and Behavior
Since recorded history began, humans have been attempting to categorize living creatures into species. Until relatively recently, this classification has been based almost entirely on visual cues – appearance and how animals behave.
In the 18th century, naturalist Carl Linnaeus created the binomial nomenclature system that we use today to arrange species in a hierarchical manner, with similar species branching off their common ancestor. Charles Darwin is credited with publishing the first credible theory about how species have evolved through natural selection.
Both of these notable scientists used observable clues to delineate species and formulate their contributions to the field of biology, since DNA analysis had not yet been invented. However, even to this day, an animal’s appearance and behavior are still important factors in determining different species.
DNA
However, there are many situations where a certain animal may look very similar or even almost exactly the same as another, yet the two are distinct species that cannot breed with each other. This is particularly common in nocturnal mammals, but the converse can also be an issue for dogs – Great Danes and Chihuahuas look almost nothing alike.
So, since visual cues are not always 100% accurate for dividing up species, scientists are placing more and more importance on sequencing the DNA of various organisms and comparing them to determine true differences in species.
Ability to Produce Viable Offspring
Finally, the most telling criterion for whether two animals are the same species is whether they can mate and produce viable offspring. This means that the two animals can have babies which can themselves mate and have babies. So, for example, horses and donkeys are distinct species (with different numbers of chromosomes) who can mate and produce mules, but mules are sterile and can’t produce offspring of their own, meaning they aren’t viable offspring.
Interestingly, although wolves and dogs are separate species, they are still interfertile, which means they can mate and produce viable offspring. However, this rarely occurs in the wild, since the behavior differences (back to that first criterion) generally prevent the intermingling of the two species.
So, this brings us to the big question…
Can Great Danes and Chihuahuas Produce Viable Offspring?
From a logistical standpoint, it is very difficult if not downright impossible for a Great Dane and a Chihuahua to naturally conceive offspring.
It is particularly improbable and actually dangerous for a female Chihuahua to carry Great Dane/Chihuahua babies, since beyond the impracticality and cruelty of a male Dane and a female Chihuahua physically doing the deed, any resulting fetuses would grow much too large for the mother’s body to handle, rendering the whole pregnancy and birth process potentially fatal to her as well as the babies. If the mother is able to carry the puppies to viability, a C-section will be required.
On the other hand, it is technically possible for a female Great Dane to carry a male Chihuahua’s puppies, but artificial insemination would be required since, again, the logistics don’t really work there. Artificial insemination is a very expensive process, and not many breeders are willing to invest that kind of money for such a risky endeavor.
While this “designer” breed mix has been achieved in the past, the resulting puppies generally require breeders to manually feed them, since they can’t nurse from a mother who is either way too large or way too small. The resulting dogs have been called Chi-Dane-Danes as well as Great Mexican dogs. They are typically about twice the size of a normal Chihuahua when they reach adulthood, and share physical characteristics of both breeds.
But, when mixing any two breeds (or even when two members of the same breed mate), there is always the possibility for genetic mutations that could either be good or very bad.
Also, while these Great Dane/Chihuahua cross breeds are generally able to reproduce, there are so few of them that to date, no examples of a Great Dane/Chihuahua mix mating with another such dog have been documented.
To truly create a new dog breed, at least three generations are required, and so far only one generation has been produced. That’s not to say that a Chi-Dane-Dane couldn’t breed with yet another type of dog, though.
So, to sum things up here, a Great Dane and a Chihuahua could technically mate (artificially) to create viable offspring (with significant human intervention). The potential problems that arise are largely caused by the size difference, the ethics of the situation, and the possible genetic mutations that could occur – but the two breeds are without question the same species.
Further details about the breed mix are outlined in this video:
Dog Breeds are a Human Construct
Finally, let us remember that all dog breeds are the result of humans interfering in the breeding process, causing artificial selection as opposed to natural selection. For example, someone long ago chose the smallest puppy from one litter and the smallest puppy from another litter, and eventually mated them together, producing a litter of slighter-smaller-than-average dogs. They then repeated that process over and over again until we got the Chihuahua.
The same selective breeding, but in the other direction, is how Great Danes ended up so large.
Dogs don’t necessarily take breed into account when they are naturally mating – to a male dog, a female dog of any breed is still a female dog. It’s actually hypothesized that if humans suddenly stopped controlling which dogs were bred together, all dog breeds would eventually meld into a sort of universal dog breed. Medium-sized dogs would serve as the bridge between the extremely large and extremely small breeds like Great Danes and Chihuahuas that can’t naturally breed with each other.
Final Thoughts
Great Danes and Chihuahuas are the same species, even though they cannot naturally conceive viable offspring. However, since humans are responsible for the insane size difference, this makes sense – artificial selection has been at play for hundreds of years. Plus, we can still enjoy the company of Great Danes, Chihuahuas, and every breed in between, without embarking on any risky interbreeding missions!
