In the June 2009 Scientific American (unfortunately not yet available on the web), Steve Mirsky proposes we make dog breeds separate species. He quotes Jerry Coyne’s new book Why Evolution Is True:
If somehow the recognized [dog] breeds existed only as fossils, paleontologists would consider them not one species but many — certainly more than the thirty-six species of wild dogs that live in nature today.
I think that’s a good point, and probably true. Dog breeds would not interbreed in nature, thus making them separate species.
Mirsky highlights the differences between an English Mastiff and the Chihuahua:
Take two that Coyne highlights for their differences — the 180-pound English Mastiff and the two-pound Chihuahua. They’re both considered members of Canis lupus familiaris, and in principle artificial insemination could produce some sort of mix or possibly an exploding Chihuahua. But face it, the only shot a male Chihuahua has with a female Mastiff involves rock climbing spelunking equipment.
Biologists clearly continue to include the two types of dogs within the same species out of modesty. But with creationists fighting evolution education throughout the country, the time calls for bold action. Let’s reassign the trembling, bug-eyed Chihuahua to its own species.
It makes sense to me, but it won’t make a difference to creationists. If anything, they will see it as a sign of desperation: “See, they don’t have any evidence for evolution, so now they’re creating new species out of thin air!” (I guarantee you Ray Comfort will say almost those exact words.)
If it is done, it should be because it’s the best thing to do, not to try and convince creationists.
Mirsky ends with a great one-liner:
Calling a Chihuahua a wolf is like calling someone at the Discovery Institute a scientist.
Indeed.
So what do you think — should some dog breeds be separate species?
I think you should still use the scientific term for the difference between a breed and a species.
If you put a big dog egg or sperm together with a small dog egg or sperm you will get a cross breed.
You can’t breed between species.
The donkey and the horse which we know occasionally create fertile offspring), the lion and the tiger, and a variety of bird species show differently.
I don’t agree — it’s that they don’t breed in the wild. There are many separate species that can breed through artificial insemination but are still considered separate species. Just look at all the cat species, for example.
At least that’s the definition of species I use. There are a number of competing definitions, but that is a commonly accepted one.
The official definition, or at least the one I learnt in biology, is that members of species can bread together to produce fertile offspring. Crossbreeds such as the mule or liger are not fertile so lions and tigers are still different species, all be it quite closely related ones.
If we use the biological species concept (yes, there are actually multiple ways to define species, but this one is most common) defined by Mayer as such: “Species are groups of interbreeding natural populations that are reproductively isolated from other such groups”, then the very small dogs would certainly be separate from large species of dog. There is mechanical isolation between the reproductive organs of a Chihuahua and a Great Dane. It just doesn’t fit! However, not all breeds need to be put into their own species. Many are still able to reproduce together naturally and probably would if left to form wild populations.
As such, I consider it scientifically acceptable to divide our current dog “species” into multiple species and not just something to be done in order to convince creationists.
Pets are not “natural populations”.
What is a “natural population”? If we are all existing in the world in various ecosystems, then are we not all part of a “natural” population of species– whatever that species may be?
Yes, you can’t mate a chihuahua with a mastiff, but you can mate them with dogs slightly larger or smaller fairly successfully, and continue so on up the chain until their genetics intermingle.
However, he does make the point that skeletal differences don’t always mean enough genetic difference to determine a species, which is something to remember for palaeontologists…
The problem with fossil classification of species is that there could very well be what we determined to be separate species that could have interbred but we will never know that since we have no living species to find that out.
‘Yes, you can’t mate a chihuahua with a mastiff, but you can mate them with dogs slightly larger or smaller fairly successfully’
Too right; my beloved doggie is – get this – a Jack Russell Terrier crossed with a Doberman! Hoorah for determined daddy (the Jack Russell)!
PS Very important point though – I wonder if this could happen all over the doggie world? As in, so long as the smaller partner was the male I don’t see a problem. A huge male dog and small bitch would obviously lead to problems but if it’s the other way round it obviously works fine. My dog’s mum had previously been bred with other thoroughbred Dobermans resulting in stillbirths, and the Jack Russell was another family pet and it just didn’t occur to the owners that it could happen! But lo and behold, it did, and it resulted in 9 beautiful, healthy pups. The size difference between a Jack Russell and a Doberman is pretty huge so I don’t really think there’s an argument for them being separate species. Interbreeding works fine as long as the male is the smaller one and he manages to physically do it in the first place!
What–did someone strap him into a pair of stilts?
Chihuahuas ARE a seperate species, some sort of rat, I think.
If you can breed between them, and the offspring is fertile, then you do not have different species. But you may have “varieties”.
Define fertile. Mules an hinnies can breed with each other and produce offspring (albeit with a greatly reduced success rate) as can tigons and ligers. Are you saying that donkeys and horses are the same species? Or Lions and tigers?
More distantly relate species cannot even produce infertile offspring. It’s very clear that there’s a continuum of relatedness between animals, where the more closely related a species is, the more likely you are to get a viable hybrid, There just isn’t a hard and fast cutoff where more similar animals are the same species and less similar are different species.
Ring species blur the edges even more – if subspecies A and B can interbreed perfectly, and so can subspecies B and C, does that mean A, B and C are all the same species, even if A and C cannot interbreed at all?
It all makes perfect sense from an evolutionary perspective (and no sense at all from a creationist perspective) but it does make taxonomy a real headache.
Taxonomy is always going to be a headache, as it’s an attempt to map things with multi-dimensional continuous properties into discrete categories. If it’s scientifically pragmatic (however you care to define that) to “elevate” dog breeds to species, then by all means let’s do it. A couple of caveats, though:
1) Most dogs are mixed breeds (at least according to this random page on the Internet, so these classifications wouldn’t apply to most of the individuals we’d be attempting to classify.
2) My guess is that domesticated animals aren’t very interesting to most evolutionary biologists anyway, so it’s not really pragmatic for them to make the time to
taxonomizetaxonifytaxonolatesort animals that they’re not studying much.Yes! That’s the concept I was thinking of…
Dogs are on their way to being a ring species, but they still have the genetics to interbreed perfectly right now. So, all one species.
Cats have been interbred with caracals, servals, and Asian leopard cats. Does that make them all one species?
The issue of where you draw the line between remote verieties and close species has been around for a long time. In the Origin Darwin dedicate a chapter to this issue where he present the point that since evolution is gradual it is going to be impossible to pinpoint the spot where varieties become species. As people has pointed here there are cases where two separate species will have fertile offsprings while others wont. It can get even worse since there are cases where if you breed a male from species A with a female from species B you will get hybrids that are compleely fertile while breeding a male from species B with female from species A will results in no offsprings. 150 years later the issue have not resolved but gut even more disputed. As for the topic of this post I don’t see any benefit in changing the definition of dogs.
The danger isn’t that creationists will say something silly, the danger is that
some eugenicist might apply it to humans – there must be some pretty hefty
skeletal differences between, say,
http://www.smh.com.au/ffximage/2007/07/15/tallshort_wideweb__470x358,0.jpg
those two.
If we’re going to talk to the creationists, this discussion’s useful for pointing
out that ‘species’ is a set of definitions for grouping together ever-changing
populations, not a list of ‘kinds’ created by God to stock the Garden of Eden.
I don’t buy that. Just because they’re two different sizes doesn’t mean their skeletons aren’t the same(Allowing for things like stretching and compressing). If they were male and female their skeletons would be more different than how they are now.
You just get done telling us it’s a scientific issue, and then you ask our opinion? My opinion is that my opinion is irrelevant. I want to know what the relevant scientists think, and, more importantly, what their arguments are.
I don’t know…I can see both sides of the argument.
I personally think they should be divided up into their root species and sub-species. I mean, that’s what breeders are trying to do anyway. I think the only difference, and possibly why people are resistant to it, is that it’s people doing the breeding selectively for traits, not nature picking and choosing for survival.
I have to disagree with Pascalle. You can interbreed between different species if they’re in the same family. Granted, in nature they wouldn’t interbreed, but it’s possible. Take the polar bear hybrids they’ve found in the arctic. It’s not normal, but necessity. Both polar bears (Ursus maritimus) and grizzlys (Ursus arctos horribilis) are in the same family (Ursids), but they’re technically different species. That said, I think it just makes sense to classify dogs into their different species and sub species under the family Canis. I’m sure there are records dating back a good long way of the origins of the what came from where. As, yes it is rather ridiculous to say that, scientifically a Chihuahua and a wolf are the same thing.
The only question I would have is what to do with the mutts? I mean I have witnessed a Jack Russel win a dog fight with a Husky over rights to a St. Bernard (and seeing him try to take the prize was just really amusing…). It’s quite possible that they don’t want to reclassify dogs into species because of all the strays. You can’t honestly say that it’s survival of the species for a Jack Russel running with a pack of neighborhood dogs to have it’s way with a St. Bernard. It’s simple dominance and pack order.
This is not quite the same, but it is an example of what amounts to genetic sub-speciation within what is supposedly one species – the Gouldian finch.
http://tinyurl.com/pqb3gr
Incidentally, I have seen the peculiar-looking offspring of a very determined Jack Russell terrier and a very patient rottweiler. I do think that taxonomy in general is not nuanced enough to consistently describe all of the differences in animal groups, though. I guess dogs are a ring species, given that genetic material could pass through the entire population assuming appropriate matings. Whether you would want to pass any of the characteristics of chihuahuas to the wider dog population is another matter!
Can we skip species and reclassify genera? Can we reclassify the Chihuahua as a type of rodent?
I’d second that.
I think rodents may find your suggestion offensive.
Hamsters especially.
Chihuahuas are shameful, despicable rodents.
Versus creationism, it doesn’t matter either way, because creationists do not feel bound to logic, coherence or consistency in their arguments (not even starting on empiricism). Make them different species (the dogs, not creationists and humans) and they will retort ‘see, it takes intelligence to create species’ *smug smirk*. There is nothing you can say or demonstrate to convince them if they’re not ready and willing to be convinced. These are people who think that making up miracles left and right for which there isn’t even scriptural evidence just to preserve Teh Flud is an honest and decent way of discussion.
So we have made dogs into a ring species (http://en.wiktionary.org/wiki/ring_species).
I don’t think the distinction is scientifically warranted. And it is absolutely true that this would be a waste of time as far as the creationists are concerned.
Now, here’s an interesting idea however. What if we deliberately bred a distinctly new species of dog? I can’t imagine it would be all that hard to do, and I don’t really see anything ethically wrong with it. No, it still would not convince the a die-hard creationist–they are not convincible by definition. But it might be illustrative of to the more average person of what scientists mean by speciation, and push the creationist to put a little bit clearer definition of whatever the hell a “Kind” is.
I propose that we turn a dog into a sea mammal using “guided” selection. It might take several hundred generations, but I think that the very process would be a wonderful example of how evolution really works.
Just food for thought…
That would be the coolest scientific experiment ever.
What about horses? Then each and every horse breed is a different species, as well; take a miniature horse and a Shire and you have the Chihuauha and Mastiff situation.
In anyway, I ask, what about genetics? Are they genetically that distinct?
I’d have to disagree with the choice but because of how some people would choose to then apply the practice to humans. Maybe it’s just me but I can totally see some people using the seperate dog species as an argument for the inferiority of other races. Anyone else picturing some evangelical preacher screaming about God choosing his/her race over all others? How about some idiot trying to spout off some quasi-statistic about the increase of learning disorders or down syndrome in ‘mixed children?’ Personally, I’m picturing some of my in-laws already formulating this.
While it is a slippery slope, human history is riddled with examples of such extremeties.
If two animals can mate and create a viable offspring on a consisten basis, then they are a species.
Actually, the way genetics works, “mixed” children have a better advantage evolutionarily speaking because they have a less likely chance of inheriting two copies of a mutated gene that confers a disorder.
“Pure” bred people- like the European royals- have all sorts of problems!
Anyway, philosophers of science have something to say about species:
http://plato.stanford.edu/entries/species/
Basically, species are a unit of taxonomic classification, but genetics makes the task of separating more closely related species a difficult one. It isn’t until two species are genetically unable to produce offspring (ie the sperm simply won’t fertilize the egg) that speciation is clear cut, but up to that point, there are degrees of relatedness.
As others have pointed out, this makes perfect sense from the perspective of someone versed in evolution. The creationists can talk all day long about their “kinds” but until they provide a definition of what “kinds” means, it is just rhetoric.
LRA,
Is the classification of species eg. dogs the same as the classification of human races? Sorry for the lack of knowledge in this field.
“Races” is an archaic term that’s generally been replaced with “subspecies” in modern scientific discourse. Darwin used it frequently when talking about different breeds of pigeons, though. And the word even made it into the title of Origin.
But it’s generally accepted that H. sapiens is not divided into subspecies. In essence, the differences between subspecies are greater than the differences within a subspecies. For humans, the opposite is true; the average difference between a Swede and a Maori is less the the difference between two random members of the same group.
Thanks wintermute. Hope scientists would publish articles that can help people like me to know more.
I appreciate your inquiry, DM! Yes, humans have much much more in common than different! We are all one human race!!!
He made from one blood every nation of men to dwell on all the surface of the earth, having determined appointed seasons, and the boundaries of their dwellings…Acts 17:26
ha! yes, we are one blood… however we were made!
Like to know if there are other sites to learn without interference
from religious bling.
I like these:
http://www.sciencedaily.com/
http://www.scientificamerican.com/
Happy reading!
Of course, if you’re interested in primary sources, there’s this one:
http://www.talkorigins.org/faqs/comdesc/
Bookmarked.
Cheers.
Is there a easier one before I embark into talkorgin?
Anecdotal evidence seems to falsify that statement. Clearly there are some physical limitations like in the example that make inter-breed copulation unlikely; but the prevalence of mixed-breeds at the pound seems to clearly indicate that dogs interbreed with abandon.
Obviously some would, I wouldn’t argue that. But the likelihood of a Chihuahua and English Mastiff breeding in the wild is very, very, very small.
But the likelihood of a Mastiff and a Labrador? The likelihood of a Chihuauha and Shitzu? A Bulldog and, well, any dog at all? I think that distinction is only really visible in the extreme breeds – Chihuauhas and Mastiffs, Great Danes and Shitzus. But the other “gradient” breeds are much closer and mutts are far too common.
I don’t know, sounds as artificial to me as saying Miniature Horses and Shires are different species, since they obviously can’t interbreed.
This seems strangely appropriate to the thread.
Elemenope ftw. That was hilarious.
Well, the majority of dogs aren’t Chihuahuas or English Mastiffs.
Also, most chihuahuas probably wouldn’t even survive in the wild very long, much less breed.
>But the likelihood of a Chihuahua and English Mastiff breeding in the wild is very, very, very small.<
I have to disagree with you on this topic, and in the above conclusion. First of all, the likelihood of a Chihuahua and an English Mastiff simply living in the wild is very, very small. So small that I doubt there is any empirical evidence for just what would happen if those two dogs found themselves alone in the woods, and became friends, if not lovers.
I also think where there’s a will, there’s a way. A sleeping female Mastiff might not even notice the attention of a male Chihuahua, for example. Or the female might not even care, asleep or awake. I’m sure there are other scenarios, too.
It’s not likely a Busman from the Kalihari Desert would mate with a professional basketball player, either, but it’s possible. That it isn’t likely doesn’t mean they wouldn’t be the same species.
For that matter, I’d like to know more about the differences between wolves and dogs – the latter come, via human manipulation, from the former. There is enough of a difference between the two that, by temperament alone a wolf would be disinclined to have anything to do with a dog, other than eat one (assuming the dog is not a Great Pyrenees).
By the same token, there are some vicious dogs that wouldn’t mate easily with any other dog, let alone a wolf.
So as difficult as pinning down what a species is or is not, I think all dogs are indeed one species, just as tall Zulus, rotund Eskimos, and pale Swedes are one species.
Oh, good grief! Most of the modern dog breeds exist because of a fad among Victorian ladies for breeding dogs for show. This grew out of the eugenics movement which Hitler was so fond of, believe it or not (on a side note, the appalingly bad health and genetic paucity among pedigree dogs is one of the strongest arguments for the stupidity of eugenics).
If left to breed naturally as nature intended, the “purest” (normally the most inbred) streams of pedigree dogs would die out anyway, and the rest would become unidentifiably mongrel through succesive breedings.
So no, they shouldn’t be classed as different species, because they’re not different species. Frankly, the whole article sounds like a horribly racist precursor to renewing the old and ridiculous claim that black people are of a different species to white.
In all the third world countries I have visited, where there tends to be little human interference in dog breeding, I’ve seen mostly what I call “third world yellow dogs”. They all look pretty much the same and are pretty much the same size. These dogs probably could trace their heritage to pedigreed dogs brought in from this or that country back in various colonial days. Dogs left alone breed with whatever dog lets them, and the end result is a sort of homogeneity. In nature, chihuahuas would have never come to be on their own. I almost hate to say this, but dog breeds are the result of, yes, intelligent design. Man, not nature created chihuahuas.
I always wondered why dog breeds being so different are classified in the same species.
“Dog breeds would not interbreed in nature, thus making them separate species.”
First off, whoever said this has not been witness to a female dog in heat surrounded by every free-roaming male dog within sniffing distance (intact or not). Dog breeds, if left alone, would most certainly be breeding together, even though the logisitcs of some matings might make it more interesting…
Dogs don’t really see breed the way humans do–they just see dog.
Second, we wouldn’t HAVE such a range of dog breeds in nature–there is nothing “natural’ about the dog breeds. Only very strict breeding protocols can keep breeds going, and it is very easy to breed them almost to death–some breeds can no longer bear young without medical intervention because humans have so screwed them up.
Know why we don’t see packs of wild poodles roaming the plains? Because poodles aren’t natural. Let them all interbreed and eventually you end up with something that looks more like the few non-domesticated species.
Yes, the odds of a mastiff and a chihuahua breeding in the wild is low, because neither breed exists in the wild. Put them, unfixed, together in the same yard, however…I have a friend whose female Great Dane was assaulted by a neighbor’s intact male chihuahua. :)
And that we keep making up new breeds by crossing existing ones: labradoodles and cockapoos, for example, show that they are quite capable of interbreeding.
Heck, my two mutts show that dogs breed where they can…
Dogs, schmogs.
Fabulous Miocene primate fossil published
Given that feral dogs interbreed with abandon, although it might make sense to split dogs from wolves, it probably doesn’t make sense to split dog breeds from each other. (To say nothing of the fact that some dog breeds are getting inbred enough that they are likely to die off in purebred form — if a type of animal can’t survive without breeding outside its “species”, then I suggest that the species label has been misapplied.)
But the majority of dog breeds could never occur in nature, because we breed for the adorable traits that also happen to hinder survivability.
To some degree. But it’s generally not the promoted traits themselves that make dogs unfit, but the secondary deficiencies caused by forcing those traits from a limited gene pool, ie. in-breeding.
Although I’ll grant you that a poodle released into the wild wouldn’t last more than a couple of days.
Not only that, they’re also adapted to their domestic environment. Methinks it’d happen as it usually does with feral horses: they’ll level to a common denominator that is fit to whatever environment they’re inhabiting.
I wonder, what would a community of feral poodles evolve into?
The Rockettes.
How long do you think a pack of feral chihuahuas would last?
Whoa. I just did a Google search on “feral chihuahua” and I am astonished by the number of links.
Feral poodles??? LMAO!!!
“So what do you think — should some dog breeds be separate species?”
Nah, but I’d surely like to see that exploding creationist due to artificial insemination.
I guess my question would be – did Noah put 2 of every breed of dog on the ark? That’s a lotta dogs. Wouldn’t that conclusively settle the question as to whether or not they were different species? We need a theological expert here. John C, where you at?
Well, we’ve only had all the dog breeds we have now for a few hundred years, but I guess 3000 years ago there were a few…
Anyway interesting article on doggie genetics:
http://www.sciencedaily.com/videos/2006/0704-doggy_genes.htm