Dogs range from tiny to huge yet cats range from small to slightly bigger. Is there something in the genes of dogs that give them more variation in size or is it simply due to more experimentation with the breeding process?
It’s probably not genetic. “Small cats” exhibit a size continuum from house cats to mountain lions. Just as importantly, the phenotypic differences across that size range is almost entirely related to scaling. So it’s inconceivable that cats are incapable of being much bigger.
And it’s not down to experimentation, since dogs ranged in size from fox terriers to mastiffs 2,000 years ago, long before anybody experimented with breeding.
The reason is twofold. The first is simply that dogs are useful for multiple purposes, whereas cats are not. Because of that people have unintentionally selected for dog breeds. That isn’t the result of experimentation, it’s more akin to natural selection. A dog has a a litter of 6 pups every year. which is far more than anyone could afford to keep. Until the last 50 years or so the standard response to this would be to keep them all until they were old enough to work, see how they went and then keep only the best. Additionally any dog that exhibited unwanted traits later in life was also killed. That was a very strong selection pressure for dog breeds, and entirely unintentional for most of history. People weren’t breeding towards a fox terrier or a mastiff, they were just keeping the most successful hunters and sharing the pups of those dogs with their friends. That led to a dogs with very different shapes and sizes, but it was never deliberate. Indeed, until the 18th century there is no evidence that people even understood that animals *could *be deliberately bred.
The second point, that dogs can be easily restrained and cats can not, adds to the first. Because cats can not be restrained it becomes nearly impossible to even breeds cats even if you want to, much less accidentally. All the dogs in a kennel or even a whole village will rapidly conform to the best phenotype through selection simply because the whole pool is being subject to the same selection pressure. Even without deliberate selection, only animals with desirable traits will ever get to breed. In contrast domestic cats mate unrestrainedly with feral/wild cats continuously. Even very strong selection pressure will be swamped by a continuous influx of genes from wild Toms. Because of that it becomes impossible to produce cats breeds. 200 years ago Charlie Darwin noted that the only true breeding cat varieties on the planet were found on small islands, and he guessed the reason. That constant influx of genes from wild Toms is going to make it impossible to select for cats that`are significantly larger or smaller. There is an minimum size range for a fighting Tom, and there is a maximum range for an animal living on the diet of a domestic cat. Any animals outside those specifications is going to lose out in the mating game.
It’s because the kittehs are perfect just the way they are.
ETA: Since they are aliens, they are immune to natural selection.
I saw some science show that said canine genes were especially prone to differentiation. It takes only a few generations of preferentially breeding tame foxes to get all kinds of “doglike” behavior, barks, and coat color variations. They believe the same thing happened with tame wolves to produce our dogs. Apparantly, if you breed for one trait, you get a lot of bonus traits along with it. This show made the point that dogs are much more prone to variation than most other animals.
I want to own this one.
If they were using **fox **breeding to prove that pet dogs are more adaptable, they missed something somewhere - foxes aren’t anywhere near the same branch of the family that results in dogs.
For a quick check, look at this tree (yes, I know, wiki, but it’s useful sometimes)
It’s not really a good conclusion anyway, because these foxes were bred specifically for ‘tameness,’ not for any specific job that would entail body adjustment. The majority of the changes in those foxes are cosmetic (infantilization) and in attitude - no real size changes occur there.
In another point, various wild fox species still have a much slimmer range of absolute sizes in comparison to dogs. They’re a little more size-altered than wolves, yes, but still, nothing like our dear familiaris.
I’m with Blake on this one - it is much more likely to be due to human-selection for specific traits in dogs, where really cats were more tolerated for their general usefulness, and no attempts were really made to breed them - they just sort of hung around. I don’t think outside of Egyptian priestly castes, any corollary to “houndskeeper” or “dogboy” really existed for cats, which is telling.
I guess that depends on what one means by “it’s / it’s not genetic.” At least one study suggests that genetic factors seem to have made it easier for humans to change dogs rapidly – which doesn’t necessarily explain the diversity itself, but does mean it seems to be easy to change dogs. See below.
Sure, humans selected for traits (consciously and not). But it may be that dogs are genetically predisposed to more rapid change:
As previously reported here. (Science Daily link in that post).
Thank you, Sailboat. I was pretty sure I remembered the gist of that show but was at work and wasn’t able to go googling around for a cite.
Hells yeah! Cheetah Cat would be awesome!
You might want to actually read Belyaev and his theories of domestication. Just cuz you read a recent National Geographic article doesn’t make you an expert.
That’s a pretty Ocicat.
The size of cats ranges from small kitties to lions that are bigger than any dogs.
Genes control the size of all animals, given adequate nutrition. The purpose of “experimentation with the breeding process” is to manipulate the genes, including those for size.
I suppose cats have been less amenable to domestication and less trainable for tasks like guarding & herding, pulling sleds & fishing nets, etc. so you don’t see as large a size range in “house cats.”
They run from $500 to $22,000.
My dad has promised to get my son a dog…but after seeing these things…we’re hoping to persuade him to purchase us a (lower ‘breed’) cat.
And I hate cats. But these little hybrids are badass!
Yabbut lion=panthera leo and moggy=felis catus.. While all dogs, from the most neurotic Yorkie to Great Danes that would make Mr. Ed nervous, are canis lupus.