Don’t forget about other diurnal raptors, corvids & shrikes, which are also true cooperative hunters (although Harris’ hawks, Galapagos hawks & brown-necked ravens are the only ones I know of that hunt in packs of 3 or more).

“and I’m pretty sure it has a much bigger brain/body ratio”

Brain structure can tell us so much more about possible intelligence (See “Conscious Critters”: http://www.time.com/time/magazine/article/0,9171,2008867-2,00.html ). Based on brain structure (See Walsh & Milner 2011), eudromaeosaurs probably had the intelligence for pack hunting.

“but why is it never on the list of possible models?”

To be fair, there’s Bakker (“In all details of their body construction——hips, knees, ankles, feet and hands, eyes and brain—raptors are designed like ground-running superhawks”: http://books.google.com/books?id=6LSERLP3BFsC&pg=PA5&dq=%22raptors+are+designed%22&hl=en&sa=X&ei=Ch4nT8rdBKrr0gHY1PC9AQ&ved=0CDYQ6AEwAA#v=onepage&q=%22raptors%20are%20designed%22&f=false ) & Fowler et al. ( http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0028964 ).

Apart from the obvious stuff about hornbills etc, the medium-sized hawk /Parabuteo unicinctus/ lives in extended family groups and regularly hunts cooperatively for prey larger than itself, with several individuals attacking the same rabbit or hare. We’re talking about wolf-level cooperation here.

Now, it’s not the world’s greatest model for dromaeosaurs or tyrannosaurs – it’s tiny and fragile, it’s highly specialised for flight, it’s not that closely related, and I’m pretty sure it has a much bigger brain/body ratio – but why is it never on the list of possible models?

As Bekoff pointed out, Coppinger’s model is based on the faulty assumption that wolves don’t communicate while hunting (among others). As indicated by the Stevens quote, pack hunters in general communicate while hunting.

Quoting Stevens ( http://www.nytimes.com/1993/01/19/sc…ted=all&src=pm ): “As used by Dr. Ellis and his colleagues, the term requires that the foraging pair or group be a stable social unit; that some members, in a division of labor, sacrifice their own prospects for a direct kill in deference to the group interest; and that group members share in the spoils.In the most complex forms, raptors exchange signals to coordinate the hunt and cooperate in hunting outside the breeding season.”

At least they do have long legs for a crocodile. This is one of the couple living in Skansen Akvariet in Stockholm:

http://planeetanihmeet.files.wordpress.com/2011/12/img_1738.jpg

Seeing a crocodile in its own element was rather scary, actually.

I found this:
http://www.thefreelibrary.com/_/print/PrintArticle.aspx?id=141091822

Apparently, at least one source of claims about pack-hunting in Cuban crocodiles is a tooth found stuck in a giant ground sloth bone found by the fossil hunter Barnum Brown. The reasoning is that the croc couldn’t have taken that big prey alone and must have attacked in groups. I find this doubtful at best. It would be interesting to know is anyone has attempted to rule out scavenging.

Not that I think simple “guys, let’s all bite the same sloth instead of attacking one each” kind of pack hunting would be necessarily outside the boundaries of crocodilian intelligence.

Later parts of the article describe the commands and tricks that can be taught to captive Cuban crocodiles. They do seem surprisingly intelligent.

I’m pretty sure I read that stuff about wolf fossil record before 2009, so it might just be outdated now, not when it was written. And, well, it’s not strictly about the modern wolf.

Social sabertooths? I have heard it suggested before, but didn’t know about this evidence. Cool.

Good to know the pack-hunting model study has been criticised (though I can’t access the article, so I don’t really know why). Could it be, anyway, that it might apply to predators other than wolves?

W/all due respect, why? Based on what I’ve read (E.g. http://www.nytimes.com/1993/01/19/science/rabbits-beware-some-birds-of-prey-hunt-in-packs.html?pagewanted=all&src=pm ), pack hunting in birds is comparable to pack hunting in wolves.

“The idea that some theropods (and yeah, inevitably, especially dromaeosaurs and tyrannosaurs) may have lived in groups seems to be the subject of more debate, disagreement and hyperbole on the web than any other subject (and I bet there’s more coming in the comments), and yet there is remarkable little actually written about this in the literature.”

In reference to tyrannosaurs, my opinion is this: As Witmer has shown (See 19:10-20:10: http://www.videozer.com/video/9Y177Zn ), large theropods probably had the intelligence for pseudo-cooperative (I.e. Communal) hunting, but not true cooperative (I.e. Pack) hunting.

In reference to dromaeosaurs, my opinion is this: As indicated by the adult-only clump (E.g. Ostrom 1969), multiple shed tooth (E.g. Maxwell & Ostrom 1995) & trackway (E.g. Li et al. 2007) evidences, Eudromaeosaurs were probably social predators (be it communal or pack hunters); As indicated by the brain evidence (E.g. Walsh & Milner 2011), Eudromaeosaurs probably had the intelligence for pack hunting; AFAWK, there are no large terrestrial hypercarnivorous endotherms that are social predators w/the intelligence for pack hunting, yet don’t hunt in packs; Therefore, combining said evidences makes pack hunting Eudromaeosaurs probable.

Actually, there is fossil evidence for pack hunting in wolves ( http://171.66.127.192/content/5/1/81.short ). Whoever said otherwise didn’t do his/her research (Shame on him/her).

“Sorry to bring the wolves back to conversation, but what to make of this study?
http://www.sciencedirect.com/science/article/pii/S0376635711001884”

As Bekoff has shown ( http://www.newscientist.com/article/mg21228380.500-wolf-smarts.html ), Coppinger’s model doesn’t apply to wolves.

Could you send me a PDF of your mutual sexual selection paper please?

As for the rest of your comment, yes all pertinent stuff. But I don’t want to say much about it as a lot of this is covered in an ongoing manuscript of mine!

While I think the statements above (Darren’s) to be relatively true, and analysts/observers drastically undervalue the complexity of behavior in lizards, crocs, and so forth, frequency matters too: Adaptability and flexibility in tool use functions and social group dynamics (whichever groupings separate “snake balls” from meerkat colonies or wolf packs) tend to appear in higher frequency in more avian and mammalian groups, while no nonavian reptile seems to use tools. The flexibility of the brain seems to have quite a bit to do with this, including how often an ability might be employed.

Well, hah, yeah, but only up to a point, right? After all, mating has to happen somehow! Unless, of course, somebody discovers evidence of parthenogenesis in dinosaurs (at first I meant that as a joke, but it’s been demonstrated in some reptiles and even birds, hasn’t it?).