Mammals Preyed on Dinosaurs?

Anonymous Howard writes "Nature is just one of many sites reporting that 130 million-year-old fossils unearthed in China suggest that contrary to conventional wisdom, some early mammals were large enough to prey on dinosaurs. Evidence? How about the fossil of a large badger-like animal with the bones of an entire baby dino in its gut?"

Comments

Blurb a little misleading...

[mOoZik]

..as it makes it seem the mammals were larger than the dinosaurs people typically think of, like the T-Rex or others, who are very, very large. But according to New Scientist, they were only around a meter long (and smaller) and would prey on very small dinos.

Re:Blurb a little misleading...

[g0dsp33d]

Well, I suppose the time period's version of the darwin awards would kick in for the ones that snuck up and bit a T-Rex.

Re:Blurb a little misleading...

[pilgrim23]

The true question here is: If a Mammal eats a Chinese dinosaur, an hour later is he hungry again?

You can prove a negative

[AtariAmarok]

Negative vs positive is just a quality of an assertion, like like green and purple are colors. Besides, any "negative" can be reworded into a "positive", which means that you can equally prove either.

Evidence?

[Engineer-Poet]

Over at Pharyngula the claim is that the tooth structure and muscle attachments on the jaw indicate the strength that is characteristic of a carnivore, not a scavenger.

What do you expect of "journalists"?

[Engineer-Poet]

However, the idea of mammals as predators upon juvenile dinosaurs goes back a long way. One of the older hypotheses about the demise of the dinosaurs is that mammals developed a taste for eggs and ate them into oblivion.

Re:Alternate interpretation

[Tyreth]

I don't think they need to explain. It's quite obvious that it being eaten is the simplest explanation. You said yourself the first interpretation is probably correct - so the reasons for rejecting the others are clear to everyone.

What instead should be asked is how you can base a new cultural tendency (mammals ate dinosours) to just a single piece of evidence. Perhaps this mammal was unusual in its eating habits. Perhaps starvation led it to steal food it would never otherwise consider. Perhaps it is normally the prey, but was fortunate enough to chance upon a wounded baby dinosaur.

I think those are more interesting points - one baby dinosaur in a mammal's stomach does not indicate anything much.

Re:bigger photo

[flyingsquid]

I have not read any of the articles on this, but when I heard the NPR story, I wondered what evidence they had against it simply being a scavenger along the lines of a modern hyena?

Well... um... because that wouldn't be as cool.

Seriously, I'm a paleontologist and that's the best answer I've got. I can't think of any good way you could rule out the idea that it just picked up some already dead dinosaur, but the scientists probably chose to downplay that possibility since it wouldn't generate as much media attention. However it's more than likely that the biggest mammals attacked and killed the smallest dinosaurs. The biggest mammal in the Late Cretaceous was the carnivorous marsupial _Didelphodon_ (about the size of a modern opossum, maybe cat-sized) which was probably large enough to tackle the tiny chicken-sized velociraptors of the time. The jaws on it are pretty darn large and massive, so it might even have been able to kill a hatchling T. rex if it got a good bite or two in. It's all fairly speculative, although once in a while you get lucky.

There's a specimen of _Velociraptor mongoliensis_ locked in combat with a _Protoceratops_- apparently they were working each other over when they were buried alive by a sand dune or a sandstorm or something.