Quoth Blake:
What definitions are you using for “stray” and “feral”, that they’re not synonymous here?
Well, feral males do tend not to get neutered, if that has an effect.
Are they saying that mammals keep growing larger after adulthood? That doesn’t make sense. I thought that a steer, bull, or cow when it’s slaughtered is about as big as it’s ever going to be. Is this correct or not?
What about he notion that ancient humans very strongly selected for wild dogs/wolves with neoteny to make them more amenable to training? If this is the case aren’t we effectively dealing with a population largely comprised of selective mutations that can never be bred back to the original type?
I’d guess that “stray” means “domestic animal escaped or abandoned to the wild” while “feral” means “raised entirely in the wild with no experience of domestic life”.
Well, I’ve certainly seen my share of cats raised without direct human intervention, from parents who were likewise not pets, and most of them have been smaller than typical domesticated cats. Even the ones that seemed to be on top of the heap were still smaller than wild-types.
You have identified the problem with tracking the process of domestication. Simple breeding doesn’t easily eradicate genes, but the great variation in dogs may be an indication that mutations were heavily favored and dogs can’t revert back to a wolf form. Dogs aren’t just different from wolves in body form either. There is a major change in the size of the head, brain, and cardiovascular system. It seems likely that dogs have returned to the wild, mingled there genes with other canis varieties and been re-domesticated, multiple times.
Neoteny is a good explanation for the traits domesticated dogs were originally bred for. Despite the theories of dogs being kept by humans as working animals for hunting or protection, they may simply have been pets. Humans are easily attracted to and amused by pups of all the species. The animals that were eventually domesticated may been selected individuals that maintained juvenile characteristics like dependency into adulthood. The utile function of dogs could have developed later through breeding.
However it happened, there isn’t clear evidence of when dogs diverged significantly enough from wolves to produce an animal that reverts to a common non-wolf form as described by Blake. This could have happened before or after domestication.
A stray is a former pet. Feral means it is part of a population that has been breeding as non-pets for “x” generations.
In general usage a stray is a domestic animal that is no longer confined.
In US usage a stray refers to a city cat that has no fixed abode. Most are actually fed by people and many sleep indoors.
Either way, they aren’t living the life a a feral and are unlikely to be hunting anything larger than rats. In contrast a feral is an animal that has reverted to wild lifestyle and lost all contact with humans. Feral cats are often bloody huge. I wasn’t joking when I said that they are significant predators on lambs.
Yes, but where were these cats living? Were they rural cats that were obtaining most of their food from rabbits, as feral and wild cats do? Because I find it hard to believe that a cat smaller than a moggie can successfully hunt rabbits. It is that need to hunt large prey that drives for large individuals in wild populations. If the cats you saw were typical strays then they were living mostly on stolen catfood and mice and rats. No selection pressure for size there.
In contrast genuine strays are huge, with a ~5kg median size in some locales. 5kg is a huge cat, and with a median of 5 kg a lot of individuals were >6kg, which makes them larger than a wild cat.
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Most mammals stop growing at some stage, but that stage is always well after adulthood. Consider what size you were at age 15, the age when you were well into physiological adulthood.
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Most cattle are slaughtered at 2-3 years for economic reasons. Heifers will keep growing until they have their first calf or until around their 4th year, whichever comes first. Bulls will keep growing into their 6th year.
This doesn’t address the problem though. If dogs were unable to revert then it would be case closed. They can;t revert. But dogs do revert, regardless of ancestry. They just don’t revert to a wolf, they revert to a yellow dog. Which indicates that the common ancestor of all dogs was a little yellow dog, not a wolf.
As you point out, dogs have been backcrossed with wolves constantly through their history. If they were wolf descendants then we would expect the descendants to revert back to wolf stock because they still carry recent wolf genetics. But they don’t. Unless they are 1/4 or more wolf then they revert to a little yellow dog. That’s puzzling.
This is all further complicated because of the constant debate of which extant canids are and are not wolves. The red wolf, for example, is either a breed of grey wolf, a distinct species or a hybrid of grey wolf and coyote, depending on which expert you ask. The Asiatic and Indian wolves are either distinct species or grey wolves, depending on what expert you ask. With that degree of confusion on extant species that have been kept relatively pure, it seems more likely than not that other, equally distinct, species were around 20, 000 years ago. If one of these was the primary ancestor of the dog with some wolf introgression then we would never be able to tell, for the same reasons that we are unable to tell whether a red wolf is a species, a hybrid or a subspecies.
I agree with you. I just don’t see enough information to determine how different dogs are from wolves, or when they diverged. And yes, the same problem applies to all the canis variations. Dogs clearly have a distinct genetic structure that most likely occurred before domestication, and was a factor in the domestication process. Specific genetic structures affecting body form could also have developed after domestication. But they are less likely to persist outside of deliberate breeding unless the dog was already distinct from the wolf at the time of domestication.
Could an animal with the appearance of a wild dog be the common ancestor of the wolf and domestic dog?
Is it possible the wolf evolved from a wild dog looking ancestor through natural selection, and then the domestic dog evolved (to a point, definitely in appearance, and because of this possibly loss of sexual interbreeding between several species of domestic dog) from a wolf ancestor through artificial selection?
Could it then be that when domestic dogs are able to inter-breed freely, they revert to the common ancestor looking wild dog instead of a wolf?
After some converting, no, 5 kg is not a huge cat. It’s a bigger cat, yeah, but I’ve got two pampered housecats bigger than that, one quite a bit bigger and he isn’t even fat. No way would his main prey be bunny rabbits, though, unless you have some mighty small bunny rabbits in the Land of Metric. I was under the impression that the ancestral wild cats pretty much ate lizards, little mammals, bugs, etc. In other words, normal cat prey.
Pigs. Not in a ‘pigs-ear’ way, in a ‘revert to wild type’ way.
My Beagle is a direct descendant of rabbits and squirrels because she keeps trying to “reunite” with them whenever she sees one.
My sister has a cat about that size, maybe a bit bigger, and he used to bring home pieces (sometimes still alive) of rabbit and possum. They couldn’t keep a bell on him, but they eventually figured out that if they fattened him up a little he lost his edge, and the problem mostly stopped.
Regarding feral dogs not reverting to wolf phenotype. Let’s keep in mind that the dog is almost certainly the earliest animal that was domesticated. We are basing our “rule” about reversion on animals that have all been domesticated for a much, much shorter time period than dogs have. I’ve seen lots of different estimates of when dogs were domesticated-- anywhere from 14k years ago to 100k years ago.
Could it be possible that dogs are the outlier for this rule because of the length of domestication?
It’s certainly possible. The reversion to wild form is assumed to be a return to the ‘normal’ genetic pattern of a species, based on the idea that breeding doesn’t eradicate genes from the original ‘normal’ form, and that form is based on probabilities within a random distribution. But breeding could introduce a mutation unlikely to become prevalent in a wild population that causes a change in body form.
The domesticated dog hasn’t been kept continuously in the control of humans for the past 10K to 100K years though. Dogs have become feral, had opportunities to remingle their genes with other canids, and been redomesticated again, certainly many times. This implies a distinct genetic structure that isn’t easily displaced by other canis forms. Based on the limited observations of evolutionary change in mammals, that would make it seem more likely that the degree of change exceeds the level breeding would produce.
There are other considerations though. Unique mutations can occur at any time. Species changing mutations are rare, but must occur occasionally to get the diversity of animals that exist. Breeding may also be able to change the genetic distribution within an animal group sufficiently to change the survivability of factors for that animal. If the distribution of genes in dogs makes smaller size more probable, the different body structure of wolves may be disadvantageous at the smaller size, while the little yellow dog provides the optimal form.
My point of view is based on the speculation that humans would not have been likely to domesticate grey wolves, as they are known now. I’m trying to find examples of other animals where breeding for temperment produces a change that survives reversion. Pigs and cattle make bad examples because the males don’t seem to change their temperment greatly through breeding. Domesticated cats don’t seem to behave that differently from some of the wild forms. I think it most likely that dogs were domesticated by humans because they already displayed a temperment that humans would find desireable.
Of course there are bigger domestic breeds. The biggest wildcat ever recorded, however, is ~6kg. So a 5kg cat is huge by any standard.
In many areas rabbits comprise something like 80% of the diet of feral cats, with an average cat size of 5kg. Maybe your domestic cat won;t hunt rabbits. Hell, most domestic cats won’t hunt rats. Cats aren’t hat stupid, they could get hurt hunting large animals. But when they don’t have a walking can opener available to them, they can and will hunt rabbits.
Ancestral wildcats, like every other animals on the planet, eat whatever they can to stay alive. If that is bugs then they will eat bugs. If it’s rabbits and lambs then they will live on rabbits and lambs.
My response would pretty much mimic Tripolar’s.
Before the establishment of agriculture, a domesticated wolf would always have been backcrossing with wild wolves, just as the domesticated dingoes in Australia constantly backcrossed with wild dingoes. And by constantly I mean that >50% of pups born have a wild parent. There is simply no way to prevent this happening. So even if dogs were domesticated 100, 00 years ago, they were routinely hybridising with wolves until 10, 00 years ago. So no scope for eliminating genes there.
Even after the advent of agriculture, dogs have always gone feral. They have always outcrossed with wolves and jackals. Many, many lines have deliberately introduced wolf genetics.
In fact wolves have less chance of remaining isolated from their ancestor than most other species because they lived side by side with those putative ancestors until just a couple of thousand years ago, at the latest. The vast majority of grazing animals never encountered their wild ancestors for most of their history because they were rapidly exterminated. So, for example, it’s highly unlikely that any individual horse has wild ancestry more recent than 4,000 years ago, and unlikely that any individual cow has wild ancestry more recent than 2, 000 years ago. In contrast it would be astonishing if there is any dog on Earth that didn’t have at least one wolf wolf ancestor within the last 1, 000 years, and the genetic evidence tells us that various dog breeds are more closely related to various wolf populations than they are to some other dogs.
Yet despite all that, the dog always reverts to a yellow dog. Even two dogs that are more closely related to wolves than to each other both revert to yellow dogs. That’s some pretty damn strong evidence that the dog phenotype is a real genetic artefact.
Feral cats have long been blamed for the precipitous decline in the brush rabbit population in Golden Gate Park since the 1970’s. Of course brush rabbits are pretty little guys as bunnies go - a two pound rabbit should be well within the wherewithal for any domestic cat.