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Cats and Dogs

I've always known this, but I found myself recently thinking about morphological diversity in canid and feline species and saying to myself, "Huh. I wonder why that is."

Canid species in the wild have a certain amount of mass a shape diversity, ranging from the fennec fox (massing between 2/3 and 1.6 kg) up to the gray wolf (massing between 36 and 45 kg). However, domestic dogs have a much larger variety of sizes and shapes, ranging from the Chihuahua (between 1.3 and 2.7 kg) to the English mastiff (massing up to 113 kg!).

The morphological variation of feline species, on the other hand, lines up in the opposite way. Domestic cats can range in mass from 2.7kg (the Singapura) to 11.3 kg (the Maine coon). But wild cats have a range of sizes that dwarfs even domestic dogs by comparison. The title of "smallest wild cat" is shared by two species, the rusty-spotted cat and the black-footed cat, both massing between 0.9 and 1.6 kg. And, of course, the largest wild feline in the world is the Siberian tiger, which can mass up to 325 kg!

Crazy. The largest dogs in the world are about the same mass as a large human, but there are four species of wild feline that consistently outmass humans: the cougar, the jaguar, the African lion, and the tigers (yes, there is more than one kind of tiger, but they all outmass humans by a large margin!).

Oh, but guess what? Humanity has outdone nature in one respect: it has bred the single largest feline species in the world, the Liger, which can mass up to 410 kg.

Here, kitty, kitty...


( 9 comments — Leave a comment )
Apr. 9th, 2014 01:39 pm (UTC)
Better to think...
of plasticity across a single species, rather than variation across genus (or larger groupings). Yes, there's a variation between domestic cats (felis domesticus) and various wild cats, but f. domesticus is a different species from panthera tigris (for example).

The domesticated dog (canis lupus familiaris) is a subspecies of canis lupus (as now placed). So the dog varies from chihuaha to mastiff within a single species. (And note - c. lupus and c. lupis familiaris can and do interbreed to produce fertile offspring). Foxes and dogs cannot interbreed - different species (that being the definition of same, really - unable to interbreed and produce fertile offspring in the wild).
Apr. 9th, 2014 01:54 pm (UTC)
Re: Better to think...
Yes, I'm aware of all this. What I'm marveling at is the fact that, with dogs, the largest variations exist within one species, whereas with cats, the intra-species variation is comparatively small. And, conversely, the range in size among all wild Felidae species is humongous, wereas the range in size of all wild Canidae species is pretty small.
Apr. 9th, 2014 02:48 pm (UTC)
We've only needed "house" cats to be big enough to eat rodents, historically speaking. Any larger and they become less cute? (Yes, a Lion or Tiger is cute, but not when they're eating your face off.) Dog diversity, I suspect, has to do with tiny dogs in the wild might not live so well, tasty coyote snacks, I'm very sorry to say. Large dogs also might not do so well in the wild either, look at all the health issues that Great Danes and other large dogs have and those are domesticated.

I suspect that humans can use a larger size range for dogs, as those are more easily controlled, than for cats. (And face it, cats and dogs are only bred as they are usable by humans.) But then I'm just kind of pulling this out of my arse as I sit here, so what do I know?
Apr. 9th, 2014 03:08 pm (UTC)
Oh, it makes perfect sense to me. I was just musing upon the idea that we bred a species (dogs) to have a larger morphic diversity than all other species in that family combined. (And also upon the fact that felids just have a ridiculously big size range, period.)
Apr. 9th, 2014 03:13 pm (UTC)
Yeah, exactly! I guess I'd never pondered it much before. And true, how large of a dog do we really need?
Apr. 10th, 2014 12:10 am (UTC)
What do you know about the savannah cat?
Apr. 10th, 2014 03:02 am (UTC)
Mostly that it's not considered a "truly" domestic cat by most cat breeders. It's a cross between a particular breed of Felis cattus domesticus and the Africal serval. And yes, they are, or at least can be, larger than Maine coons, but I wanted to be safe in my choice for the "largest" domestic cat. Using the savannah cat as that example just felt a little bit like cheating.
Alan Kellogg
Apr. 10th, 2014 10:28 pm (UTC)
There are people who don't think Felis silvanus libbica in any form qualifies as a domestic animals. And yes, the two populatins are that closely related. Besides, you're the creative type, you're supposed to cheat.
Apr. 10th, 2014 08:13 pm (UTC)
Couple of thoughts- we didn't breed for larger house cats because felines are much more dangerous than a canines, pound for pound, and temperamentally more likely to be aggressive. I mean, which is scarier... a snarling German Shepherd or a pissed off tortoiseshell of the same size? My mom's 15 pound Siamese kicked a German Shepherd's butt; and the dog naturally outweighed the cat significantly, so I know my answer. ;) Also, while the smallest cats and the smallest dogs mass about that same, it looks like, based on your research, canines may not have developed larger sizes in the wild due to their society. A wolf pack takes down a deer in concert, but a tiger does it alone, and thus needs to be larger.
( 9 comments — Leave a comment )

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