Hello, everyone! Welcome to Freak Week- a week devoted entirely to animals that makes NATURE spit her soda out in sheer WTF at. Although nature has made some pretty darn weird stuff herself, this week will be devoted to the most freakish breeds that mankind has mustered thus far.
Breeds. Not species.
"Wait, those are different?" you ask. Yes, they are. They are very different terms with different implications in modern society. They are different in terms of where they are found. Hell, they are even different on a linguistic level. Have a demonstration:
Imagine, for a second, that someone wanted to ban a certain breed of animal - say, pit bulls - from a certain area in the U.S. OK, no big deal - pit bulls are just one breed of dog, and they just so happen to be a breed specifically bred to fight in arenas. Dog fighting is illegal in most states. Since pit bulls are named and bred for that sport, a ban on pit bulls is a (horribly failed) attempt to curb illegal dog fighting. Normally, only pit bull owners and dog lovers will care about such a thing. After all, it's only one breed of dog, right?
Now for a contrasting scenario, imagine a ban on all species in the genus Python. That 2000-dollar piebald ball python (P. regius) that will never ever get more than 6 feet in length is suddenly put on the same level as the Burmese python (P. molurus bivittatus), which is only related at the generic level. The two do not share dietary habits, natural habitat, or sexual compatibility on a regular basis. They are not the same species. This came VERY close to happening, in part because of the confusion between "breed" and "species."
"Breed" denotes a certain type of domesticated animal. They are standardized, showed, and recorded. For example, Golden Retrievers and Labradors are both breeds of domesticated dog - Canis lupus familiaris. Holstein and Jersey are both different breeds of cattle. My tabby cats are a different breed from the hairless cats seen in Austin Powers and Lady GaGa's "Bad Romance" video. They are the same species of animal, but different breeds.
I still cannot tell whether this is a Canadian or Russian hairless. The ears don't look big enough to be a Russian, but part of me hopes that GaGa did her homework. No, I could not resist using a "Bad Romance" cap.
For a more technical definition: " A breed is a group of domestic animals or plants with a homogeneous appearance, behavior, and other characteristics that distinguish it from other animals of the same species. When bred together, animals of the same breed pass on these uniform traits to their offspring, and this ability—known as "breeding true"—is a definitive requirement for a breed."
Thanks, Wikipedia. So, what does that mean in real life?
If you breed, say, two Scottie dogs together, you will get nothing but Scottie dogs. No retrievers. No dogs that look like wolves. No Labradors. Just little, yappy black dogs that look like they were pulled off of a flapper girl's skirt. They look like Scotties, walk like Scotties, and bark like Scotties. You're pretty damn sure that you have a family of Scottie dogs on your hands, with all the temperaments, quirks, and appearances of their parents.
Scotties can mate with any of those breeds mentioned above, as well as wolves. On a regular basis. With no decrease in fertility. In the 'wild,' i.e. the dog park. This compatibility is, in part, what makes Scotties their own breed rather than their own species. Even then, they would be a subspecies of the subspecies Canis lupus familiaris - yes, the domesticated dog is still a wolf, albeit a subspecies.
Here's why: Not only are dogs descended from wolves to begin with, but they can interbreed with ease, and the hybrid pups show no decrease in fertility. Any dog with any wolf in them within 5 generations is technically considered a wolfdog. The same is true with dingoes, another Canis lupus subspecies (which is technically a domestic dog turned feral). This is NOT true with coyotes, who not only have a premating barrier VS dogs, but whose bastard pups tend not to be very fertile. (I have heard conflicting info concerning coydogs in particular, but whatever the case, they don't do it very often.)
Yes, this is all about mating and survival of the fittest - just like Darwin's Origin of Species. There are, however, some differences between the selections that make a species and the selections that make a breed.
Let's look at the definition of 'breed' again, this time in PowerPoint form:
1. The animal in question has to be considered domesticated.
2. It has to look and behave differently from others of its species.
3. It has to breed true. I don't want a wolf in my litter of Scottie dogs.
Now, in greater detail:
1. Your mileage may vary on the term "domesticated." I have heard anything from 'has to be able to breed in captivity' to 'must be trainable and submissive (e.g. have some form of social hierarchy, allowing humans to be recognized as a 'leader')' to be considered domesticated.' In many cases, the domesticated form of a species differs greatly from, and sometimes replaces, the wild ancestor (as in the case of Bos taurus). For example, a Russian scientist bred silver fox (Vulpes vulpes) kits that were the least afraid of humans together; the results paralleled the changes that had occurred between C.lupus lupus and C. lupus familiaris.
2. This is really broad. For this, you need to find the 'wild-type'- i.e. the form and type most commonly found in the animal's natural habitat. Then, compare it with a captive specimen. Using out Scotties as an example again, let us put a Scottie alongside a gray wolf. The two look and act differently, but they would still be sexually compatible. There might be a size issue, but that would almost be like saying that a normal person can't make out with a dwarf.
3. When I breed Scottie dogs, I WILL get Scottie dogs. There was someone that I once met on my bike route who had lost a purebred Scottie in the past; she wanted nothing except another Scottie dog to fill the hole in her heart, even though it would cost a LOT more to purchase than a random shelter dog. The Scottie's personality, physical characteristics, and other differences from other dog breeds out there all had a hand in her decision. She knew how a Scottie dog would act, how big it would get, what it would look like, and how to take care of it. She could not have done this with any other dog, even though they are all Canis lupus familiaris. Even a Scottie cross would not do; breeding out cuts down the predictability of traits.
This is different from speciation on a number of levels. The definition of 'breed' is limited to domesticated animals - again, your mileage may vary on that term. Breeds are deliberately created for certain qualities, both physical and temperamental. They are substantially different from their wild counterparts, but not differentiated enough so as to prevent sexual compatibility.
I have been using Scotties thus far as an example of a 'breed.' It is a well-known breed with a decent amount of crosses, and has had good exposure in pop culture. I have had an experience in which someone wanted a Scottie and nothing else - a testament to its status as a true breed, not a mutt.
Let us look at a few things that are not breeds, and then at what makes a species a species and not a 'breed,' shall we?
Morphs are the traits most commonly mislabeled as 'breeds.' An albino animal is not that different from a wild-type member of the same species - it is a horse of a different color and nothing more or less.
As an example, Labradors can come in many colors (such as golden, chocolate and black, to name a few). These are all color morphs. In the wild, color morphs can vary with locality or be a simple recessive, dominant, or co-dominant trait. By definition, a morph must exist in the same wild population as at least one other morph.
In captive populations, when a morph deviates from a breed standard, as is the case with Holstein cattle, the morph may branch off into its own breed. It's pretty much a paint job most of the time.
Always putting the red folk down...
Although the Greek word 'morph' means 'form,' more often than not, the term is applied to some sort of color variation. In any case, the morph is usually one trait (although many traits are linked to some other trait, such as crossed eyes in white tigers). Breeds have many, many traits associated with them. That is why furred hairless dogs are still considered the same breed; there are other traits that make the breed. (Also, the heritability of hairlessness means that SOME furred puppies are inevitable.) Morphs can be one part of a breed, just like eggs are one ingredient in a cake.
Hybrids are also not, technically, breeds. I do not mean 'hybrids' like a Scottie-whatever mix; I mean mules, wolfdogs, coydogs, beefalo, zorses, ligers, jungle corn snakes (corn x king), Borneo Bateaters (retic x Burm), and other such crosses. Those are either species crosses or subspecies crosses. While they may have been induced in captivity (lions and tigers no longer share territory in the wild), they are still not breeds.
A Borneo Bateater, a fertile hybrid between Burmese and reticulated pythons. There is some debate over whether it is a natural intergrade or not...but DAMN if it isn't awesome!
Remember criterion 3: It has to breed true to be considered a breed. Some of those hybrids do not breed period, or have reduced fertility, mostly because of chromosomal differences. Even in hybrids that can breed, the abnormal ratio of parental DNA means that they will not necessarily look exactly like their parents, nor that their natures can be determined with consistency. Generally, hybrids are a one-time deal, and the results afterward are by no means steadfast. They are not themselves considered breeds, but can, like morphs, be grouped within breeds (e.g. German Shepherd x coyote).
Subspecies, although genetically compatible with other members of the species, are also not usually considered 'breeds.' Although they do breed true and differ sufficiently from other subspecies (there is never only one subspecies; the term is reserved for two or more), they are often not domesticated, and never seen as captive breeds. Unlike breeds, they are recognized as a scientific class due to their differences - for example, Morelia spilota cheynei VS Morelia spilota spilota.
A species refers to, again as per Wikipedia, "a group of organisms capable of interbreeding and producing fertile offspring." I would personally add "in their natural environment," or "frequently," but there is really not much to be said beyond that. Sure, there are DNA sequencing methods of determining species, but if you really want to debate whether Burmese and ball pythons are the same species or some such, just remember that they have different habits, live in COMPLETELY different environments, and only one is sold at Petco these days (with good reason).
AS OF RIGHT NOW, THERE ARE NO BREEDS OF SNAKE - JUST MORPHS, SPECIES, AND SUBSPECIES.
To be fair, the albino Burmese python (P. molurus bivitattus) is close to the 'breed' title. Not only are they sweet enough to cause diabetes, but they exhibit higher fertility than most other types of Burmese python, as well as having the 'calm white snake' demeanor that seems to be consistent throughout snake species (as seen in the video below).
Even unrelated snake species, such as corn snakes (Pantherophis guttatus/Elaphe guttata), have very docile albinos. The increased fecundity, however, is not consistent between different species. This is probably due to the albino Burm's nature as one of the first snake morphs on the market. (And why not? I'm not saying that EVERYBODY should have a giant pet snake, but Burmese pythons are impressive and docile. Even a wild-type Burmese python can be sweet as a kitten.)
In my reticulated python entry, I mentioned that retics were actually one of the better candidates for domestication (even by the strict definition - retics are the closest snakes have to ANYTHING with a social hierarchy). I also mentioned that Tiger retics seemed to be more docile than their wild-type counterparts. This is an excellent example of correlated traits - it does not seem like the retic has lost its intelligence or famous/notorious ability to recognize its owner, and has less of a temper than other morphs. People who own and handle retics well often get attached to them (and, to some degree, vice-versa).
Now, if only they didn't get 30 feet long as adults. Oh, wait, there are a few subspecies of dwarf retic from various little islands...that are hyper and aggressive. This correlation between small size and scrappy nature deters many a potential owner from getting a dwarf specimen. They're also more expensive than solid gold caviar, and that doesn't even exist. It will be a while before snakes develop genuine breeds, if ever.
Please, please, please do not get the terms 'breed' and 'species' mixed up! Although it may be comforting to think of all of nature as one big happy family, it is not. Burmese pythons are different from reticulated pythons, which are different from ball pythons. Not all squirrels are the same species. Cows do not only come in black and white; they come in a rainbow of shapes and a variety of sizes, and they are all the same species (be on the lookout for Bos taurus). Your macaw is not that closely related to your parakeet, even though they look like darn similar birds sometimes. If it is not 'domesticated,' it is not a breed.
With that said...On with the freak show.
Sunday, July 25, 2010
Breeds VS Species.
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