# If humans vanished, would dog breeds merge or speciate? **URL:** \ **Category:** Great Debates\ **Created:** [February 3, 2014, 4:07am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399 "2014-02-03T04:07:26Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [February 4, 2014, 12:12am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/41 "2014-02-04T00:12:25Z")
> [@BrainGlutton](#): > > Nitpick: You mean “helpless”; with no humans around, “useless” no longer applies. Nah, I meant what I said… 😃 ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [February 4, 2014, 12:13am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/42 "2014-02-04T00:13:25Z")
> [@nevadaexile](#): > > My St. Bernard-Boxer mix might disagree with that statement What the story behind **that?!** ---
**Author:** ![Tastes\_of\_Chocolate](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tastes_of_chocolate/32/3232_2.png) [@Tastes\_of\_Chocolate](https://boards.straightdope.com/u/Tastes_of_Chocolate)\ **Post date:** [February 4, 2014, 12:15am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/43 "2014-02-04T00:15:56Z")
> [@Miller](#): > > On the other hand, the main driver behind evolutionary change is environment, and what sort of environments are these dogs going to be living in after humans are gone? Ruined cities aren’t an issue - they’ll be completely reclaimed by nature within a few centuries. But some environments might end up selecting for traits that were artificially introduced into dogs in the first place. Terriers and other dogs bred for hunting rodents and burrowing animals might find themselves flourishing in a post-human environment, while larger dogs find more success as wolfish pack hunters, eventually leading to two distinct species. But you’d need to have a breeding population of those terriers or ratters, to create a seperate line. Maybe if there was an area with a high density of terriers (like… New York outlaws all dogs except terrier breeds) you would get this, but with the almost random distribution of pet dog breeds, that wouldn’t be likely to happen. ---
**Author:** ![drewtwo99](https://avatars.discourse-cdn.com/v4/letter/d/d07c76/32.png) [@drewtwo99](https://boards.straightdope.com/u/drewtwo99)\ **Post date:** [February 4, 2014, 12:17am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/44 "2014-02-04T00:17:55Z")
I like the bit of logic that says that breeds that are better at certain things may end up speciating. ---
**Author:** ![Miller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/miller/32/481_2.png) [@Miller](https://boards.straightdope.com/u/Miller)\ **Post date:** [February 4, 2014, 12:30am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/45 "2014-02-04T00:30:34Z")
> [@Tastes\_of\_Chocolate](#): > > But you’d need to have a breeding population of those terriers or ratters, to create a seperate line. Maybe if there was an area with a high density of terriers (like… New York outlaws all dogs except terrier breeds) you would get this, but with the almost random distribution of pet dog breeds, that wouldn’t be likely to happen. Not necessarily - you just need a bunch of dogs in an environment that favors small dogs that can dig into rodent burrows, while disfavoring large dogs that can’t. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [February 4, 2014, 1:24am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/46 "2014-02-04T01:24:37Z")
> [@Jonathan\_Chance](#): > > Yeah, somewhere here someone with some knowledge (Blake, maybe? Colibri?) speculated that feral populations end up producing smaller, yellow dogs with very curly tails. How much that applies worldwide I couldn’t tell. I seem to remember a PBS special documentary about dogs and one of the segments concerned what happens to domesticated dogs when they are allowed to freely interbreed. The case shown was an Indian city where there was a rather large population of feral dogs. Indeed they all looked basically like the above quote. I’m wondering that in the scenario put forth by the OP if the wild wolves wouldn’t return to the top of the food chain and basically eat up a majority the feral domesticated dogs and coyotes. Just my buck thirty-seven. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [February 4, 2014, 1:29am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/47 "2014-02-04T01:29:51Z")
> [@drewtwo99](#): > > I like the bit of logic that says that breeds that are better at certain things may end up speciating. OTOH, they are likely to breed indiscriminately with all other physically compatible dogs in their neighborhood, so they might not keep their distinctive characteristics. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [February 4, 2014, 1:31am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/48 "2014-02-04T01:31:46Z")
> [@watchwolf49](#): > > I’m wondering that in the scenario put forth by the OP if the wild wolves wouldn’t return to the top of the food chain and basically eat up a majority the feral domesticated dogs and coyotes. Just my buck thirty-seven. I don’t think any dog could win a fight with a wolf; wolves are too strong. But many dogs might **outsmart** a wolf; some breeds – German shepherds, border collies, etc. – have been bred for smarts. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [February 4, 2014, 1:46am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/49 "2014-02-04T01:46:45Z")
> [@BrainGlutton](#): > > OTOH, they are likely to breed indiscriminately with all other physically compatible dogs in their neighborhood, so they might not keep their distinctive characteristics. That will happen for sure long before speciation. Just look at the various mixes you have. Actually, there will be a genetic bottleneck, since a vast majority of dogs kept as pets are not going to be having any puppies. The breeding population would be from puppy mills and from puppies not yet fixed. Who would be most at risk for getting eaten by other dogs etc. BTW, fads result in lots of examples of single breeds in an area. There are 5 goldens in a half block radius near me. But I’ve never noticed dogs being too picky, so I don’t think that would help preserve breeds except by chance. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [February 4, 2014, 2:20am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/50 "2014-02-04T02:20:07Z")
> [@Voyager](#): > > I’m not sure it will take that long, since the dogs are starting out with a lot more diversity in the genome than you’d find in a species that we hadn’t messed with. > > I’d think that speciation would come from size differences which would prohibit either mating or successful births of hybrid dogs larger than their mothers. > There are lots of little dogs interested in my dog, but they wouldn’t be able to do anything without a stepladder. > There might be some geographical isolation which would help in speciation, but I don’t think we know which breeds would occupy each niche. Except that there is a clinal variation in size, so that even if a doberman never mated with a chihuahua, they would each mate with dogs intermediate in size between the two, and so gene flow would continue. And the more successful breed “hybrids” would outcompete the purebreds, bringing us right back to the Pariah Dogs I linked to, above. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [February 4, 2014, 2:22am UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/51 "2014-02-04T02:22:47Z")
> [@Voyager](#): > > Actually, there will be a genetic bottleneck, since a vast majority of dogs kept as pets are not going to be having any puppies. The breeding population would be from puppy mills and from puppies not yet fixed. Who would be most at risk for getting eaten by other dogs etc. No, there would not be a genetic bottleneck. That would only happen if the species were reduced to a very small number of individuals, like \< 10,000. There are billions of dogs, and lots of wolves and coyotes. With humans out of the way, canid predators would do quite well. ---
**Author:** ![CarnalK](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnalk/32/486_2.png) [@CarnalK](https://boards.straightdope.com/u/CarnalK)\ **Post date:** [February 4, 2014, 2:32pm UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/52 "2014-02-04T14:32:52Z")
> [@BrainGlutton](#): > > I don’t think any dog could win a fight with a wolf; wolves are too strong. But many dogs might **outsmart** a wolf; some breeds – German shepherds, border collies, etc. – have been bred for smarts. You really don’t think a pack of Rottweillers could handle themselves? ---
**Author:** ![leftfield6](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leftfield6/32/18780_2.png) [@leftfield6](https://boards.straightdope.com/u/leftfield6)\ **Post date:** [February 4, 2014, 4:34pm UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/53 "2014-02-04T16:34:48Z")
> [@CarnalK](#): > > You really don’t think a pack of Rottweillers could handle themselves? Against a similar sized wolf pack? Nope. Just my opinion, of course, certainly not willing to run the scientific study needed to prove it. IMHO, the wolves have had generation after generation of breeding nothing but survival into themselves. By the time the Rotts have acquired anywhere near this level of survival instinct, they probably aren’t Rotts anymore, based on the crossbreeding that has already been discussed in this thread. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [February 4, 2014, 4:39pm UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/54 "2014-02-04T16:39:53Z")
> [@CarnalK](#): > > You really don’t think a pack of Rottweillers could handle themselves? Not in a fight with an equal number of wolves. Wolves are **strong.** They have to be. Dogs don’t, and much of their strength has been bred out of them. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [February 4, 2014, 4:43pm UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/55 "2014-02-04T16:43:21Z")
> [@John\_Mace](#): > > No, there would not be a genetic bottleneck. That would only happen if the species were reduced to a very small number of individuals, like \< 10,000. There are billions of dogs, and lots of wolves and coyotes. With humans out of the way, canid predators would do quite well. In India the dogs would probably not even notice. In the US, however, what percentage of dogs you see walking would be able to reproduce? Not many. And what percentage of the ones who could breed would survive? I think it would take a few generations for wolf and coyote populations to reach a lot of the country. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [February 4, 2014, 4:48pm UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/56 "2014-02-04T16:48:08Z")
> [@John\_Mace](#): > > Except that there is a clinal variation in size, so that even if a doberman never mated with a chihuahua, they would each mate with dogs intermediate in size between the two, and so gene flow would continue. And the more successful breed “hybrids” would outcompete the purebreds, bringing us right back to the Pariah Dogs I linked to, above. It would be a textbook example of ring species. I think we’d see speciation at the ends, over time. The survival rates of various hybrids would determine how any splits there are. Whether or not pure breds get outcompeted, there would not be many in subsequent generations, so it wouldn’t really matter. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [February 4, 2014, 5:00pm UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/57 "2014-02-04T17:00:56Z")
> [@Voyager](#): > > I think it would take a few generations for wolf and coyote populations to reach a lot of the country. Would it? Coyotes have been spotted in **Florida** recently! ---
**Author:** ![astorian](https://avatars.discourse-cdn.com/v4/letter/a/ad7895/32.png) [@astorian](https://boards.straightdope.com/u/astorian)\ **Post date:** [February 4, 2014, 5:08pm UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/58 "2014-02-04T17:08:27Z")
> [@BrainGlutton](#): > > Would it? Coyotes have been spotted in **Florida** recently! I’m pretty sure there are coyotes in MOST states. We sure have them here in Austin, and some have even made it to Manhattan. Hawaii is the only state I’d vouch DOESN’T have them! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 4, 2014, 5:18pm UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/59 "2014-02-04T17:18:32Z")
> [@](#): > > Quoth **Voyager** : > > It would be a textbook example of ring species. Not really. The textbook ring species is geographically varied, such that you get one trait in one location, and a slightly different trait in a location next to that, and so on. But dogs of different sizes are all found mixed together: You could easily have a chihuahua, a beagle, a German shepherd, and a St. Bernard all living on the same block, easily within the range over which individual dogs will roam. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [February 4, 2014, 6:09pm UTC](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399/60 "2014-02-04T18:09:56Z")
I don’t think the “ring” in ring species need necessarily be geographical. I’d argue that dogs do qualify, because the individuals at the extreme ends of the size spectrum cannot interbreed, as has been pointed out over and over, and yet gene flow across the spectrum can, and does, still happen. But that’s just a quibble about the definition of “ring species”. [Previous page](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399.md?page=2) [Next page](https://boards.straightdope.com/t/if-humans-vanished-would-dog-breeds-merge-or-speciate/680399.md?page=4)