Enter the Dog
"It is always best to start at the beginning."In theory, if you are talking about dogs, this means you are supposed to talk about how dogs evolved from wolves.
I won’t belabor the point except to say that, while true, the statement is a bit overstated. A dog is not a wolf. A dog is a dog.
This is not to say that wolves and dogs are not evolutionarily related — this is an absolute fact. Dogs descended from wolves, probably through some form of long-lasting proto-wolf phase.
That said, the differences between dogs and wolves are not small, but enormous, governing the most elemental issues of existence, from reproduction to communication.
A wolf, for example, goes into estrus only once a year, generally in February or March. A dog normally goes into estrus twice a year, and this can occur in any season. A male dog lifts its leg to pee, while a female dog squats to pee.
In wolf packs, only the top male and top female raise their legs to pee — all subordinate animals squat to pee.
Dogs bark — it is their primary vocalization and maddeningly common, especially early in the morning when you are trying to sleep. Adult wolves bark so rarely it is almost never heard in the wild.
Wolves and coyotes howl, and do so very frequently — generally in the early evening just after waking up and before going off to hunt. Dogs almost never howl except under very special conditions and in response to sustained noises that rise and fall — like the wail of fire engines. You may have 15 dogs in your yard, but they will not howl every morning as a coyote or wolf will.
The fact that dogs, wolves and coyotes CAN interbreed does not mean they actually do except under the rarest of circumstances.
Dogs and wolves operate on completely different wavelengths, and only in the most extreme kinds of "prison romance" situations do these two animals leap the species barrier, generally only in captivity or in very rare instances when a vanguard of a species (a lone coyote or wolf in a very large area devoid of all other wolves and coyotes) finds it impossible to mate with its own kind.
In short, wolves and dogs have drifted so apart from each other that key signals related to sex, communication and hierarchy are no longer shared.
A dog is not a wolf.
Scientists are divided as to when the wolf split off from the proto-wolf, and when the proto-wolf became a dog.
What seems clear is that the lives of dogs and humans have been intertwined for many thousands of years. During most of this time humans exerted little or no control over breeding, and evolution appears to have worked its invisible hand to produce a fairly common, smallish, coyote-looking dog.
This "pie dog" or pariah dog can be seen prowling the edges of dumps the world over, looking not too different from the dingo or "Carolina Dog" favored by our Neolithic ancestors.
Genetic researchers tracking mitochondria DNA have shown that most of the dog breeds seen in Kennel Club show rings today are of very recent origin.
The supposedly "ancient" Ibiza hound and Pharaoh hound, for example, turn out to have been made up within the last 100 years or so — bred to look like the drawings and sculptures of sleek, slender-necked canines found on pharaonic tombs at the time of Carter. The Norwegian elkhound, a breed supposedly dating back to Viking dogs, was created within the past few hundred years.
And so it is with nearly every breed of dog, with very rare exception.
The terrier, it should be said, is not one of those exceptions.
No terrier breed is more than a few hundred years old, and most were created within the last 150 years.
9 comments:
The cool thing about dogs mixing with wolves, is that the offspring are completely interfertile. In contrast, although dogs and wolves can and do occasionally hybridize with other Canis species (coyotes, golden jackals, and Simien jackals), the offspring exhibit what's called reduced fertility. In other words, the first generation hybrids can reproduce, but the males produce less sperm. In the F2 hybrids, males produce still less sperm, and F3 hybrid males are sterile. Thus, not only genetically and ecologically, but also reproductively, dogs and wolves are clearly in different species from coyotes and jackals. With each other, though, not so.
Wolves do bark. They bark when they are facing prey and are trying to intimidate them into running so they can course them. They also bark at intruders into their territories. These are the same circumstances under which dogs bark. Dogs also howl like wolves. Anyone with a husky or hound knows that dogs howl when they are socially isolated, just like wolves. They also have a rallying howl for territorial defense, just like wolves. Different subspecies of wild wolves bark and howl with different regularity. Southern wolves, from which dogs descend, have vocalizations more similar to those of dogs than northern wolves. Makes perfect sense.
As for reproductive strategies, most canids (including wolves) have family units, led by the mated pair, and accompanied by previous years' growing young. However, wolves also have more flexible social structures, allowing for young males to mate with young females without forming a pair bond when prey is abundant. Dogs, which are more promiscuous than wolves, appear to usually follow this non-pair-bonding aspect of wolf mating behavior. What's more, feral dogs like dingoes, do have a pair bond. The number of estruses per year is a minor change.
Again, it's the battle of the lumpers vs. the splitters. Are wolves and dogs different? Sure. But dogs are just domestic wolves, no different from wolves than are cattle from the extinct aurochs, or sheep from mouflon, or chickens from red jungle fowl, etc. We love dogs because they are wolves that love us back.
Your opening line is simply wrong.
Dogs and wolf crosses are almost always fertile -- certainly as likely to be fertile as two dogs or two wolves crossing. The idea that species who cross are infertile is simply wrong most of the time; mules are the exception rather than the rule.
To continue, your points about barking and howling is over-wrought. Wolves very rarely bark and dogs very rarely howl -- they simply communicate in an entirely different way. Wolves howl almost every evening as territory marking behavior, the same as dogs will at night (listen this evening in your neighborhood).
There is no "battle between lumpers and splitters" with wolves and dogs -- they are separate species and the animals themselves know it and act like it, not only through culture (vocalizations, estrus, defecation, marking behavior, glands). but also through their tendency to not interbreed except under "prison romance" situations.
None of what I have said here is actually up for debate; these are points of provable fact.
I said interfertile, not infertile. Infertile means sterile. Interfertile means capable of mixing. I said dogs and wolves are completely interfertile.
Also, dogs and wolves don't only mix under prison conditions, the way cattle and bison do, for instance. Dogs and wolves have been mixing for thousands of years. Again, it's not under the pair-bonding circumstances, but rather under the "casanova" circumstances, of a lone wolf mating with a bitch in heat. Under those conditions, wolves have mated with dogs in Eurasia and North America many, many times. The hybridization rate between coyotes and either wolves or dogs is much lower.
You wrote:
"None of what I have said here is actually up for debate; these are points of provable fact."
And yet dogs are now generally considered a subspecies of gray wolf (Canis lupus familiaris), most closely related to those of southern Eurasia and northern Africa.
If you ever watch two wolves greeting each other, you feel like you're at a dog park. The ritual is the same. The excitement tinged with nervousness is the same, the vying for position is the same (barring territorial aggression, which is also much the same as in dogs). And if you've ever watched a dog and captive wolf meet, the ritual is still the same. That's not how coyotes and jackals meet each other, as they are less tolerant of their own kind and live in smaller groups. It's also not how dogs or wolves meet coyotes or jackals (usually the meeting is quite dangerous for the smaller canid).
You say that dogs and wolves just "know" they're different species, but I don't see it. I've seen how my dogs react to coyotes, and it looks like regard for a different but related species (as opposed to prey, like a rabbit). But when dogs meet wolves, there's that look of recognition. If anything, they know that they are the same, only separated by who they consider to be their pack.
Sorry -- reading on cell phone with old eyes. Yes, wolves and dogs can interbreed and are fully fertile as noted.
If you have seen wolves meet each other, you probably were at a dog park -- penned wolves have very little in common with their opposites.
In the wild, wolves from outside a pack rarely meet each other without violence coming into play. The single greatest killer of wolves is wolves, and night time howling a both a display and a territory warning. "I am here, do not come here, for we are powerful and bad things will result."
Wild wolves have been fairly well studied and their interactions documented. See this old post for video and a pretty interesting story of how the largest wild wolf pack in the world ended up disappearing. http://terriermandotcom.blogspot.com/2014/05/the-true-dominance-of-wolves.html
Hate to say it but I think The Terrierman doth protest too much! I think that it is clear that wolves and dogs are different but there are so many gray areas and inconsistencies and points of view in both science and taxonomy that I don't think anyone can say for sure if wolves and dogs are two species or sub-species or just different because of man's unnatural selection. Genetically hardly different at all, anatomically SOME dogs differ by not having a precaudal gland but some dogs do have this gland and the behavioral differences can mostly be explained by domestication. "Proto-wolf" is just a fancy way of saying scientifically a wolf long ago which MAY or MAY NOT HAVE differed from the gray wolf today. Genetically wolves and dogs are pretty much as close (99.8%) as human beings amongst themselves (99.9%). So species or sub-species or domesticated/wild the answer is definitely not that clear.
I think part of the problem in common parlance, is people are conflating different species concepts. The biological species concept (or BSC, once the most common) states that if two animals are completely interfertile (capable of producing completely fertile offspring, with no partial or complete loss of fertility), then they are the same species. However, another version of the BSC states that it's not enough to have this potential, the animals must actually do it themselves in the wild. Thus, they must be nearby and interbreed. If they are from different areas, but couldn't interbreed on their own, then they're not the same species. By this definition, wild wolves should be split up into several different species, because even though they would be completely interfertile if brought together artificially, they couldn't do so in the wild, because they're scattered all over the world (Europe, Arabia, Central Asia, Canada, Mexico, etc).
There are many other species concepts out there (just see Wikipedia for a summary), some more common than others. The species concept most often used these days is the phylogenetic species concept (PSC), which states that if two animals are very close genetically ("close" is debatable, but in practice usually 97% or higher), then they are the same species. This concept is useful, because it incorporates other species concepts, such as interfertility, mutual recognition, similar morphology, similar behavior, similar ecological niche, etc. Basically, if two animals are genetically very close, then they have not been apart for very long, and are very similar in most ways, including recognizing each other as mates, looking and acting similarly, and performing similar functions in nature.
Again, domestic animals kind of throw a wrench into the works, because although they have not diverged much from their wild cousins, they are necessarily somewhat different because they occupy a different niche (living and working with humans). Look at any pair of domestic and wild animals (cattle and aurochs, pig and wild boar, domestic and wild turkey, etc), and you'll find that genetically they are extremely close, but differ in a few key ways, usually relating to their role as domestic animals. In the case of dogs and wolves, as Jeffrey Thurston mentioned, they are phylogenetically clearly the same species (more than 99% the same). It's comparable to the different populations of modern humans (Homo sapiens sapiens), perhaps a bit more, as there is more than one living subspecies of wolf. Morphologically and ecologically, there are some larger differences, depending on the landrace or breed of dog. When it comes to reproductive compatibility, again it's open to interpretation. Terrierman considers the relatively infrequent interbreeding between wolves and dogs to indicate incompatibility, while I consider the interbreeding common enough to indicate that the two are indeed compatible.
At the end of the day, I value the phylogenetic species concept the most, and by that standard, dogs are domestic wolves.
I think part of the problem in common parlance, is people are conflating different species concepts. The biological species concept (or BSC, once the most common) states that if two animals are completely interfertile (capable of producing completely fertile offspring, with no partial or complete loss of fertility), then they are the same species. However, another version of the BSC states that it's not enough to have this potential, the animals must actually do it themselves in the wild. Thus, they must be nearby and interbreed. If they are from different areas, but couldn't interbreed on their own, then they're not the same species. By this definition, wild wolves should be split up into several different species, because even though they would be completely interfertile if brought together artificially, they couldn't do so in the wild, because they're scattered all over the world (Europe, Arabia, Central Asia, Canada, Mexico, etc).
There are many other species concepts out there (just see Wikipedia for a summary), some more common than others. The species concept most often used these days is the phylogenetic species concept (PSC), which states that if two animals are very close genetically ("close" is debatable, but in practice usually 97% or higher), then they are the same species. This concept is useful, because it incorporates other species concepts, such as interfertility, mutual recognition, similar morphology, similar behavior, similar ecological niche, etc. Basically, if two animals are genetically very close, then they have not been apart for very long, and are very similar in most ways, including recognizing each other as mates, looking and acting similarly, and performing similar functions in nature.
Again, domestic animals kind of throw a wrench into the works, because although they have not diverged much from their wild cousins, they are necessarily somewhat different because they occupy a different niche (living and working with humans). Look at any pair of domestic and wild animals (cattle and aurochs, pig and wild boar, domestic and wild turkey, etc), and you'll find that genetically they are extremely close, but differ in a few key ways, usually relating to their role as domestic animals. In the case of dogs and wolves, as Jeffrey Thurston mentioned, they are phylogenetically clearly the same species (more than 99% the same). It's comparable to the different populations of modern humans (Homo sapiens sapiens), perhaps a bit more, as there is more than one living subspecies of wolf. Morphologically and ecologically, there are some larger differences, depending on the landrace or breed of dog. When it comes to reproductive compatibility, again it's open to interpretation. Terrierman considers the relatively infrequent interbreeding between wolves and dogs to indicate incompatibility, while I consider the interbreeding common enough to indicate that the two are indeed compatible.
At the end of the day, I value the phylogenetic species concept the most, and by that standard, dogs are domestic wolves.
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