Lions and tigers and not dogs? Oh, why?

August 29, 2006 5:02 PM

Why are there no canine equivalents to lions, tigers, leopards, and panthers (etc.)?

Wikipedia says that an average domestic housecat weighs 5.5–16 pounds. It doesn't give an average for dogs, but anecdotally, 5-200 pounds pretty much covers the spectrum. Now, "the average weight for male lions is 350-530 pounds," but wolves seem to top out around 200 pounds.

Can anyone speculate as to why canines don't seem to have a vastly bigger relative in this sense? I realize that the logic behind "domestic dogs are usually bigger than domestic cats, so wild 'dogs' should be bigger than wild 'cats'" is deeply flawed, but I'm amazed at the breadth of the gap between the two.

posted by Sinner to pets & animals (19 comments total)

well.. wild dogs are typically scavengers, whereas wild cats are typically predators. dunno what difference that makes, though, but one can speculate about selection for size when you have to kill things.
posted by sergeant sandwich at 5:10 PM on August 29, 2006

This is a fun question. And lions aren't even necessarily the biggest of the big cats. See Bengal Tigers.
posted by weston at 5:11 PM on August 29, 2006

I'm pretty sure coyotes are predators, not scavengers...
posted by twiggy at 5:12 PM on August 29, 2006

Something to do with the smaller size variation of domestic cats compared to large range found in the variety of dog breeds?
posted by knapah at 5:13 PM on August 29, 2006

And Siberian Tigers.
posted by weston at 5:15 PM on August 29, 2006

Wolves are pack hunters, while lions and tigers are ambush hunters. Solitary ambush hunters need more size and fast-twitch strength to take down game. Other cats -- like cheetahs -- have different hunting strategies and are not that much bigger than wolves.
posted by frogan at 5:17 PM on August 29, 2006 [1 favorite has favorites]

Along the lines of what frogan said, dogs hunt in packs, where numbers and coordination are as important as individual size. For the most part, cats are solitary hunters. The only cats the exhibit some pack-hunting attributes are African lions, but their pack behavior is not nearly as sophisticated as dogs, wolves, etc.
posted by alms at 5:20 PM on August 29, 2006

Probably the simple answer is that big dogs didn't need to adapt to survive. Put another way, 'small' dogs do just fine and don't need to grow bigger to compete. This is just a guess.
posted by maxpower at 5:52 PM on August 29, 2006 [1 favorite has favorites]

"Scientists tell us that bears and dogs share a common ancestor. About 38 million years ago, the bear and dog lines separated into two distinct groups." -USFWS

Depending on how distant you would like to get in evolutionary branching (Miacis) as a starting point, for instance), you could say that bears are similar to giant dogs despite variation that makes them closer to sea lions structurally.

I think the gulf between domestic and wild in cats and dogs is more about the very close genetic difference between canine species and the sub-family difference of felinae and pantherinae. As mentioned before, when looking for evolutionary reasoning the somewhat omnivorous diet and exhaustive pack strategy of canines requires less weight to overcome prey than the overpowering strategy of individual or prides of cats.
posted by arruns at 6:03 PM on August 29, 2006

Keep in mind also that for evolutionary processes to "move" a population to a certain point, an ecological niche has to exist to allow that. If other animals took up the ecological space that larger canines would fill, then evolution in that direction was prevented from taking place. It's not necessarily that big ol' dog-creatures would be maladaptive in general, it's just that it was never clearly more adaptive for long enough for evolution to move a population in that direction.
posted by The Michael The at 6:21 PM on August 29, 2006 [1 favorite has favorites]

Dogs/canines seem to occupy the space between small and large cats. That's their niche, in The Michael The's words.

Taking North America as an example, there are very few animals that need the girth of a large cat. Buffalo are the largest animals we have that would be considered prey, but because they're always in packs, it would take a pack of hunters to score one. Moose are about the most solitary of large mammals, but girth doesn't help there (I've heard stories of bears found dead after they tried for a Moose. Of course, they're not the most agile of creatures).

And here in North America, we don't have the huge cats that Africa has. Our mountain lions and Panthers can get big, but nowhere near the size of an african lion.

So... basically.. ditto what The Michael The said.
posted by hatsix at 6:39 PM on August 29, 2006

The short faced bear, known as the biggest warm blooded predator ever. It was running around North America up until about 10 000 years ago. As others have said, since this guy along with the Smilodon and Scimitar-Cat (all of whom are llarge predators) were big predators maybe there wasn't enough room at the top for big dogs.

There is only so much room at the top for predatory megafauna.
posted by maxpower at 6:42 PM on August 29, 2006 [1 favorite has favorites]

This would be an excellent question to put to PZ over at Pharyngula.

I am not a biologist, but I see one or two holes in theories proposed above.

Lions ARE scavengers as well as hunters, and second, lionesses hunt together and co-operate. Following on from that, lionesses target game up to North American buffalo size (eg large wildebeest or gnus) hunting as a pride.

I agree with the idea that in North America, bears fill the niche of large solo predator. Lions used to be endemic in Europe and Asia and there are still bears there too.

But if it comes to that: there used to be very large wolves ("dire wolves").
posted by i_am_joe's_spleen at 8:09 PM on August 29, 2006

Big and small cats are in two different genus. All dogs are in one genus. Pretty big distinction there.
posted by fshgrl at 9:44 PM on August 29, 2006

Thanks for all their answers. I wish I could say I was totally satisfied by any one of them at this point, but something still doesn't quite sit right about all of it (the whole "well, it's the way evolution wanted it" argument just makes me want more).

arruns answer was the coolest, although I have to give credit to the point advanced by frogan, the michael the and hatsix.

To i_am_joe's_spleen: I read your link to wikipedia and was surprised to see the following "The common misconception of the Dire Wolf is that it was much larger than the Gray Wolf; in fact it was similar in overall size and appearance. On average it was a little larger at about 1.5 metres (5 feet) in length and about 50 kilograms (110 pounds)." Isn't that directly contrary to the point you were trying to make?

Anyway, keep 'em coming, this is all really interesting to me.
posted by Sinner at 10:02 PM on August 29, 2006

sinner you are comparing small cats/ big cats and small canids/ big canids and many of us have pointed out that's not a valid comparison as small and large cats are actually quite different, evolutionarily speaking. Much more so that dogs and wolves for example. More like dogs and foxes or dogs and bears.
posted by fshgrl at 10:25 PM on August 29, 2006

the wikipedia article about dire wolves is wrong. Dire wolves weighed about 160 lbs and were shorter and stockier than gray wolves. This is info I have gleaned working at the Page Museum at the La Brea Tar Pits. They have the largest collection of dire wolf fossils in the world (app. 200,000 specimens).
posted by anansi at 8:10 AM on August 30, 2006

Part of this argument should include the greater diversity in the cats. While there are something like 4 kinds of dog, there are more kinds of cats, 12 maybe. Further, while dogs are very similar genetically, cats aren't anywhere near as similar between kinds.

I wish I had a link to back this up, but I don't have the time to search and create links. I'll leave that up to the rest.
posted by kc0dxh at 8:51 AM on August 30, 2006

Well, the Americas did have the Saber Toothed Cats which were lion-sized. But they died out along with most of the other American megafauna. The reasons for this are a matter of much speculation.

I think an honest answer to this kind of question is that we just don't know about the specifics. It's only been in the last few years that we've been able to establish relationships among cat species and modern cats are all relatively young species, 1-5 million years or so. These are the sort of questions that lead to PhD research projects. There is an old Victorian suggestion called Cope's Rule which seems to be generally true for mammals but highly contraversial.

This is one of those weak areas of evolutionary biology. While it is a given that natural selection results in genetic changes over long periods of time, ecosystems are complex and chaotic environments and trying to puzzle out causal theories about specific factors is difficult. This is made even more difficult when you are looking at ecosystems that are now extinct (such as the last glacial maximum.) Evolution works really, really amazingly well for the big picture, but for a lot of the little details and "just so stories," there is plenty of room for debate.

This isn't just a limitation of evolution BTW. Most theories in science are deceptively simple in the abstract, and fiendishly difficult when applied to the complexities of actual cases in the universe.
posted by KirkJobSluder at 9:15 AM on August 30, 2006