Four-legged carnivorous dinosaurs?

August 11, 2010 12:50 PM

My six-year-old son wants to know how many carnivorous dinosaurs walked on four legs.

So far we've got things that weren't technically dinosaurs, like the Deinosuchus.

posted by winston to Science & Nature (18 answers total)

The Rhedosaurus. Unfortunately fictional.
posted by le morte de bea arthur at 1:07 PM on August 11, 2010

Juvenile Sauroposeidons ate small mammals.

There are really very few carnivorous sauropods. The theropods have most of the meat-eaters (although there were herbivorous theropods, too).
posted by Cool Papa Bell at 1:08 PM on August 11, 2010

Strictly speaking, there are no known carnivorous dinosaurs who walked on four legs. All known carnivorous dinosaurs belong to the suborder Theropoda, which contains only bipedal dinosaurs. Your best bet is to continue looking at things that are "dinosaur-like", but not technically dinosaurs.

My inner pedant has won the battle against the part of me that didn't want to rain on your awesome dinosaur parade. Apologies.
posted by Parasite Unseen at 1:08 PM on August 11, 2010 [3 favorites]

Whoops ... from my own link...

there's absolutely no evidence that sauropods were even partly carnivorous.
posted by Cool Papa Bell at 1:09 PM on August 11, 2010

The Spinosaurus is bipedal, but it has long front arms that makes it look more like a four-legged creature than, say, a Trex.
posted by brenton at 1:11 PM on August 11, 2010

Here is a complete list of all dino carnivores
you can google image search each one and check -

i dont think very many, if any, were four legged -
meat eaters had those front claws for gripping and tearing meat
posted by Flood at 1:11 PM on August 11, 2010

My daughter's been dino-crazy lately, so I've been watching lot of documentaries and reading books with her. It hardly makes me an expert, but I'm under the impression that the four-legged stance is an adaptation herbivores favored because it afforded extra support for their digestive tract.

With the exception of semi- quadrupedal tree-dwellers, I'm not sure there were any four-legged, true dinosaurs. My understanding is bipedalism is one of the defining differences between dinosaurs and their ancestors, and that quadrupedalism re-emerged later.

I could be waaaay off though, and I'm curious to see what answers come up.
posted by lekvar at 1:22 PM on August 11, 2010

I thought this was one of those definitional things. True carnivorous dinosaur = 2 legs. Everything else on 4 legs isn't really a dinosaur. You can tell by my lack of technical precision and references that there may yet be a better answer yet on this.
posted by kch at 1:46 PM on August 11, 2010

I'd like to amend my previous statement:

"bipedalism is one of the defining differences between early dinosaurs and their ancestors"
posted by lekvar at 2:01 PM on August 11, 2010

Yeah, I'm pretty sure that all known carnivorous dinosaurs were bipedal, but as you mention there are plenty of quadrupedal non-dinosaurian creatures that were just as neat!
posted by brundlefly at 2:07 PM on August 11, 2010

Turns out that the dimetrodon isn't a real dinosaur either ... But it did walk on four legs and eat meat. I feel cheated - it was included in my beloved childhood collection of Carnegie dinosaur models!

http://en.wikipedia.org/wiki/Dimetrodon
posted by Metasyntactic at 2:49 PM on August 11, 2010 [1 favorite]

Turns out that the dimetrodon isn't a real dinosaur either ...

Don't feel bad; take heart in the fact that they were proto-mamals! Yeah, that's right, who's laughing now, T-rex? Yeah, I thought so!
posted by lekvar at 3:00 PM on August 11, 2010 [1 favorite]

Baryonyx may have spent at least some of its time on four legs. I don't think it's believed to be strictly quadrupedal, but probably hung out on four legs at the edges of bodies of water (it was fish-eating) quite a bit, and its forelegs were strong enough to move it around a little. It was probably more comfortable on four legs than humans are but less comfortable than chimps are, for instance.

But yeah, you're going to find a lot of creatures that were carnivorous and quadrupedal but not technically dinosaurs, and a lot of creatures that were carnivorous and dinosaurs but not technically quadrupedal. Current belief is that you're not going to find anything that hits all three.
posted by penduluum at 3:03 PM on August 11, 2010

So even though quadrupedal dinosaurs are kind of considered a holy grail of paleontology, there were a few four-legged carnivorous dinosaurs out there.

For starters, a lot of prosauropods ate meat, or were at least omnivorous. I'm assuming this isn't terribly impressing to a kid, considering that there were a lot smaller than later sauropods and basically look like herbivores with pointy teeth.

There is some controversy over whether Spinosaurus was quadrupedal. The idea here is that what we thought were spines supporting the sail are shaped more like bony supports that you might find inside of a large, fatty hump. For this animal, that would work out better with a quadrupedal gait, but there are plenty of paleontologists who would argue vehemently for Spinosaurus' being bipedal.
posted by DoktorFaustus at 4:20 PM on August 11, 2010

I definitely group Dimetrodon (which I came in here to say) in with the dinosaurs. Hell, I group pterosaurs and icthyosaurs with dinosaurs. That's how I roll. Also, explaining otherwise to a 3 year old is pretty much impossible.

Also also, alternate spellings of "icthyosaurs" include "brontosaurs" and "McCarthyism". That sounds about right.
posted by DU at 4:53 PM on August 11, 2010 [1 favorite]

It might be worth mentioning that the vast majority of dinosaurs that existed aren't known because they didn't get fossilized or the fossils that exist haven't been discovered. Most of our best and most complete specimens come to us due to highly specific and localized catastrophes which quickly killed and buried the aniimals. So asking today "how many dinosaurs X" is kind of like having never seen a functional car but having access to one junk yard and trying to answer the question "How many cars X." You will give a much different answer if your junkyard is in New York than you will if it's in Mexico City.
posted by localroger at 5:40 PM on August 11, 2010 [1 favorite]

I don't really know anything about dinosaurs, but I popped in to say you are raising an awesome kid if he is asking that sort of question at 6 years old.
posted by thekiltedwonder at 9:02 PM on August 11, 2010 [1 favorite]

Response by poster: Thanks for all the responses everyone
posted by winston at 1:55 PM on August 31, 2010