Those relatively tiny arms seem utterly useless. Was there anything at all that the animal used them for?
Could the creature have had them both chopped off and lived a normal T rex life? Are they just vestigial, did they have some use, however mundane?
I know it’s not quite from a peer-reviewed journal, but I was just at the store a few minutes ago and was looking at a T-Rex floor puzzle. On the back, it said that even though it had such small arms, some scientists think it could life up to 1200 pounds (or something like that).
Don’t know who these scientists are, but at least it bears a little checking.
You might be helping to make Jack Horner’s point - Jack Horner is the paleontologist who’s been theorizing that T. Rex was a scavenger, not a predator. See:
http://montana.edu/wwwmor/trex.html
Somewhere in there, Horner says:
Elsewhere (a site not having anything to do with Horner or The Museum of the Rockies), I found this interesting note:
If it were vestigial, I don’t think you would see all that muscle development. WAG - given that it has claws on the end of it, and a lot of strength, the arm was used for ripping apart carcasses, rather than grasping or manipulating anything, whether the animal caught them itself or scavenged.
I’ve heard that question answered both ways. I tend not to buy the “no they’re too small” argument because scientists are always focusing on what dinosaurs “can’t” do insted of focusing on the anatomy and deciding what they can do.
Yes, the arms are* relatively *small and weak. But by studying the muscle attachment sights, several scientists concluded that the grip of the Tex was very strong and the arms are designed to pull things into the body. They weren’t going to reach out and grab anything, but if a hadrosaur (the primary prey of the T. Rex) got to close, those arms could hold on tight enough that the Rex could get in a killing bite.
The arms are currently part of a larger debate on whether T. Rex was a predator or scavanger. The scavenger clan, led by Jack Hoerner, claim that the Rex can’t do anything with it’s arms, can’t run fast enough and can’t see well enough with it’s “small” eyes.
In addition to what I’ve already said about the arms, it must be remembered that snakes and birds, both of which can’t use their arms, are highly effective predators.
As for their speed, the arguments that they would be slow could be applied to most anything that would be their prey. They weren’t slower than what they would be chasing.
As for the eyes, as D’Arcy Wentworth Thompson points out in *On Growth and Form * smaller animals have relatively larger eyes and larger animals have relatively smaller eyes. Plus it must be remembered that a predator/prey arms race has existed throughout history. The T. Rex’s eyes aren’t really small for a terresstrial predator in the cretaceous.
Finally it needs to be pointed out that there is **no such thing **as a terrestrial scavenger. With the possible exception of the vulture (which isn’t terrestrial, it’s avian) every animal you think of as a scavenger is a predator, some, like the hyena are quicker to scanvenge than other, but all are predators first. All known predators will scavenge if the opportunity presents itself. And as for vultures, they will actively seek prey if they are desperate enough.
So back to the arms, for the reasons outlined above, I’m always sceptical if a scientist says a dinosaur “can’t” do something. So I’m incliined to agree with the scientists who say the arms are good for gripping liong enough to get a killing bite in.
Well, I was going to say that it could flip the other dinosaurs the finger, but if it only had two claws per, I suppose it couldn’t even do that. BTW, yabob, it’s cool seeing a reference to my school-- I’m a mile from the Museum of the Rockies. Maybe I ought to go ask Jack. 
Well boys and girls other than one obvious thing it couldn’t do with those (relatively) little arms (maybe that’s why it was so aggressive all the time) let’s do a thought experiment. Who’s up for a ride in the time machine?
Grrr. I’m hungry. I stalk. I kill. I’m lowering my head to get to the carcass. I want the organ meats. I’m leaning down and burrowing into the carcass where are my arms and claws RIGHT NOW?
In a position to grasp the body and stabilize it somewhat for rending and tearing. ----------Ummm. Maybe.
Rrrrr. I’m Horny. Sniff…sniff…Yes! Wow she’s big! Better hang on this is going to be a real ride. Unnf.
Where are my arms and claws RIGHT NOW?
In a position to hang on for dear life and stabilize my purchase while mounting her. The species is continued-------Ummm. Maybe.
It’s a little known fact, but T Rex was actually a great knitter, and could crochet with those little arms. There are fossil remains of T Rex afghans.
In addition to it’s skills in knitting, it could play a fine Ragtime piano, and was loads of fun at charades!
The only thing I ever heard that the arms could be used for (and it is very weak, pardon the pun) is that if T Rex was lying prone, its arms could hold the ground and stabilize its body while its legs got underneath it
T Rex could get it on AND bang a gong.
I found that quite droll.
In addition to knitting and rag time, I’ve heard that the T-Rex used its arms for catching the slower Thesaurus (a smaller dinosaur that used flowery language to get itself out of potentially dangerous situations).
::Ducks to avoid onslaught of thrown vegetable matter::
I have come to the conclusion that T. rex both stalked and killed live prey and ate carrion, but it ate more carrion than most modern predators.
You’re all wrong. Those arms are used to aim and fire laser guns that space aliens sold to the T-Rex in exchange for colonization rights on the Moon.
The T. Rex could do three things with its arms…
It could use them to pick its teeth
It could use them to pick its nose
It could use them to hold onto other T. Rexes while dancing the “Forbidden Dance”, which would only occur once a year on the summer solstice. So those of you who can channel and see dead things can look forward to find a display next year at the “Ghosts of the Jurassic” exhibit at the “Damned Psychics Fair” in South Cairo, GA next June 21.
It could wave them in the air, like it just didn’t care.
OK, here’s the scenario…
I’m one of those little chicken-sized dinos, who just scurries around stealing eggs. I see Mister T. Rex coming along the horizon, and you think I care about what his arms can or can’t do? Of course not! I’m gonna scurry away from there just as fast as I can!
Either that or hide, pull up a chair, and watch the fun…
Earlier on the board I read a post that there were no “terrestrial scavengers”. I surprised to read this bold faced statement and even more surprised that it apparently went unchallenged. The poster said that most animals thought to be scavengers are actually predators. It’s actually the other way around. I’ve got some books on the topic but I’ve also provided a quick site that anyone can check out if they want. Some obvious scavengers: the raccoon, the rat, even the hyena has become, primarily, a scavenger. The raccoon and rat especially, and many others in the same family of animals also are totally, if not primarily, scavengers. Other animals often resort to scavenging quite often. I might also note that many insects are scavengers, but that’s beside the point. Anyway, just because there are few scavengers in the present world that you can think of off the top of your head, does not mean it was not once wildly practiced. Not to step on any religious toes but I might mention evolution as the primary reason for fewer scavengers today. Animals practicing it either went extinct or evolved. Speaking of vultures, isn’t there some sort of theory that many dinosaurs evolved into birds? I’m not able to quote anything on that but I know I’ve heard it numerous times. Maybe they evolved to the more prosperous avian scavenging. There are many other bird scavengers (seagulls, obviously). Just a thought.
Silent Rob
“I love irony.”
-Silent Rob
This info came from the Kids Almanac site:
http://www.yahooligans.com/content/ka/almanac/animals/ani00008.html
Here’s the full text on mammal scavengers…
Seven Mammals that Scavenge
Bears often follow ravens in order to find dead fish to eat. Alaskan brown bears feed on dead seals, walruses, and whales
that have floated ashore.
Hyenas hunt and scavenge in packs. African villagers often leave their garbage out for hyenas to eat.
Jackals (African wild dogs) often scavenge in packs beside hyenas.
Leopards, like lions, will scavenge when their hunting is unsuccessful.
Lions are great predators but will often scavenge or steal prey caught by other animals.
Raccoons eat garbage from dumps and cans, especially if it smells of chicken or fish.
Rats will eat anything.
well, they were a pretty good Glam band…
oh… that sort of T-rex…
Regarding the predator/scavenger debate:
Though hardly scientific, after racking my brain for at least ten minutes, I can’t think of any animal that won’t scavenge if the opportunity presents itself. After all, scavenging is the most efficient way to get fed - much fewer calories expended than running down prey.