General question on feline/canine physiology from an evolutionary perspective

[ProZackMI]

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First off, I'm an MD, not a vet, so please forgive my ignorance on this matter. Tonight, my girlfriend and I were discussing our political views and she made the off-handed comment that we are as different as cats and dogs.

Being a smart ass, I said "actually, from an evolutionary perspective, cats and dogs aren't that dissimilar and more than likely evolved from a common ancestor, and then split off forming two distinct carnivores." She just looked at me blankly.

My question is, are cats and dogs really as different as many think? Yes, they are two different species, but if you list the things they have in common, aren't they more alike than not? What do you think?

Also, does anyone know the name of the phylogenic ancestor to cats and dogs? Isn't it something like cynodictis or a miacid? It's been ages since I had a zoology class. I know everyone is busy, but if anyone knows, I'm just curious on your professional thoughts.

 

[PrimalMU]

I'm not sure about cynodictis or miacid (taxonomy gives me a headache), but I did uncover this with a bit of Googling: http://en.wikipedia.org/wiki/Eomaia

Take wikipedia with a grain of salt, of course.

I think at the core of the "difference" discussion is what qualities you are comparing. Yes, dogs and cats may be genetically related, but things like physiology, anatomy, and most importantly behavior would best determine how different two species are. And, in order to do that, you really have to go wild and look at wild felines and wild canines. Of course, then we also have to consider the genetic mishmash we've created among the different breeds of domestic dogs and cats. Certainly behavior-wise, it could be argued that domestic dogs and cats are less different than say a puma and a wolf is. In many ways it could be argued that domestic dogs are as different from wolves as wolves are from cats.

Its certainly an interesting topic.

 

[alliecat44]

I think you'd need a DNA analysis to say definitively one way or another. Plus, as PrimalMU pointed out, there are many different species of both "cats" and "dogs"--so which do you compare to which? Humans have, what, 97% or 99% of the same DNA sequences as chimpanzees, right? That's technically comparing primates to primates. Therefore, comparing cats and dogs would lead to much more dissimilar results, I'd think.

As an aside, there's a saying in veterinary medicine: "Cats are NOT small dogs!" This is because a cat's physiology is much, MUCH different than a dog's. Certain drugs are safer in one species and toxic in another, and even such treatments as fluid therapy can and are strikingly different in their application to cats and dogs.

 

[Bill59]

Cats did not evolve. They've always existed in their current, prefect state. They domesticated the inferior human species to do their bidding and cater to their whims. Then, they coerced humans to domesticate dogs so they would have a lesser species to torment for entertainment purposes.

 

[twelvetigers]

 

[ratbandit]

I usually use a website called the Tree of Life for my phylogenetic questions it's pretty darn good. Tracing my way to the domestic dog it goes...

Mammalia, Infraclass: Eutheria, Order: Carnivora, then comes the split to Suborder: Feliformia (or superfamily Aeluroidea) & Suborder: Caniformia (or superfamily Arctoidea)...

Suborder: Feliformia, Family:Felidae, Felis catus

Suborder: Caniformia, Family: Canidae, Canis familiaris

It seems that miacidae is a family branching from caniformia but has no living relatives. Cynodictis was a genus from the family Amphicyonidae which is also a family branching from caniformia but has no living relatives. I can't seem to find any single ancestor to both the cat and the dog.

 

[Electrophile]

Also, does anyone know the name of the phylogenic ancestor to cats and dogs? Isn't it something like cynodictis or a miacid? It's been ages since I had a zoology class. I know everyone is busy, but if anyone knows, I'm just curious on your professional thoughts.

Basically, you've got your caniforms (dog shaped) and your feliforms (cat shaped). I think to some degree, they are still trying to decide who fits where in Carnivora, as the pinnipeds throw a wrench into the whole thing.

From Dog: Behavior, Evolution, and Cognition by Adam Miklosi (2007 Oxford University Press) pages 68-69:

Paleozoologists agree that in the history of the Carnivores the Canidae family is represented by two extinct subfamilies (Hesperocyoninae and Borophaginae) and one living one (Caninae) (for a more detailed review see Wang et al. 2004). Species belonging to these subfamiles originated 40 million years ago and evolved in North America....The first recognized member of Caninea subfamily, the fox-sized Leptocyon, lived in the early Oligocene (32-30 million years ago).

So looks like the canids first emerged 40 million years ago or so from something else. It doesn't say what the something else, sorry!

 

[hoodle]

The hunt for the common ancestor between cats and dogs is somewhat missing the point - everything has a "common ancestor", from bacteria to plants to mammals. If you go way way back, you're looking at the mythical LUCA - the Last Universal Common Ancestor, a pre-bacterial species.

More recently than that, and more relevant to our discussion- somewhere, there was a carnivorous little beastie who existed on land, and from that little creature evolved two distinct lineages, the cat-like and the dog-like. For reference, these lineages are so broad that the dog-like category includes skunks, seals, otters, and bears, while the cat-like is similarly overarching.

Looking for common ancestors is more of a palentology question - a fossils question. More modern technique for resolving relationships involve molecular genetics and phylogenetics.

Here's the first paragraph from a paper I found on the subject: - let me know if you want me to email it to you...
A phylogeny of the Caniformia (order Carnivora) based on 12 complete protein-coding mitochondrial genes
Molecular Phylogenetics and Evolution, Volume 37, Issue 1, October 2005, Pages 192-201
Isabelle Delisle, Curtis Strobeck

"The phylogeny of the mammalian order Carnivora has
been studied extensively. The order Carnivora is traditionally
divided at the suborder level into Caniformia,
dog-like carnivores, and Feliformia, cat-like carnivores.
Both suborders are further subdivided into several family
groups. Various works based on morphological
characters (Wyss and Flynn, 1993), karyotypes (Arnason,
1977), DNA–DNA hybridization techniques (Arnason
and Widegren, 1986), DNA sequence data (Arnason et al.,
1995; Flynn et al., 2000; Ledje and Arnason, 1996a,b),
total evidence (Dragoo and Honeycutt, 1997; Flynn and
Nedbal, 1998; Vrana et al., 1994), and supertree strategies
(Bininda-Emonds et al., 1999) generally agree on the
monophyly of these two suborders and of most carnivore
families, but have failed to resolve the tree with significant
support either above or below the family level (Flynn and
Nedbal, 1998). The present work aims at resolving contentious
relationships among caniform families."

 

[ProZackMI]

Cats did not evolve. They've always existed in their current, prefect state. They domesticated the inferior human species to do their bidding and cater to their whims. Then, they coerced humans to domesticate dogs so they would have a lesser species to torment for entertainment purposes.

THAT WAS FUNNY! Thank you!

 

[ProZackMI]

Thanks, everyone. Helpful answers. Based on my lay observations, it seems like dogs and cats, while vastly different, have more in common, however, than many think.

Another observation: of the cats, the Cheetah is the most canine; non-retractile claws and dog-like sprinting. Of the dogs, the foxes are the most feline; vertical pupils, partially retractile claws, can climb trees, good mouses, solitary predators, etc.

 

[hoodle]

While these sorts of observations are really interesting and certainly valuable, I don't know how much evolutionary weight they hold... morphological analysis of species relationships is a really fuzzy area. Convergent evolution, in which different selective pressures result in similar characteristics, really messes up the accuracy of morphological and behavioral analyses. I'd stick with genetic work to identify which are the most "dog-like" cats and cat-like dogs...

 

[sofficat]

someone might have said this..... but...

hyenas are in the feline family, not the canine family 😱

 

[twelvetigers]

Hyenas a pretty strange critters to begin with!