tyrannosaurus rex size and behavior

Did not know about packs that large, but I personally see 52 feet pushing it. I think 45-48 feet tops (for any Rex, dug up or not).

Welcome! Hopefully I'm not making a bad first impression, but... I'm guessing you got this information from the UCMP toe bone or the "22 m" Rigby's Rex? UCMP is too flat and wide to belong to a tyrannosaurus. The 22 m Rigby Rex is just as much nonsense as the 25 m "Liopleurodon", 20 ton Deinocheirus and 22 m Kelmayisaurus. Basically unfounded apart from a random theory that someone threw out. The 15-16 m Tyrannosaurus comes from the same people who said a pliosaur skeleton belonged to a late cretaceous stegosaur and mistook a fossilized tree for "Bruhathkayosaurus'" femur. The team based that purely off of size and location, which everyone knows is a bad things to do. There's no direct pack hunting evidence, but I see it as fully possible. How else would they take on utterly massive and dangerous prey like Ankylosaurus and Triceratops, both of which are generally agreed upon to be able to beat a Tyrannosaurus face to face (or face to tail) As Spyrannosaurus says, reconstruct animals how they are, not how you want them to be.

DinoFights is right. I see Rex maxing out 45 feet (maybe), and I have said before (unrelated maybe), that I believe the few remains we have of Spino could have just been one of those really big ones that got really old, and I think they might have been the only bones durable enough to have survived for millions of years in the desert. Not trying to bring up Rex vs Spino (it's dead), but that my opinion. Maybe Spinosaurus averaged 46-50 (give or take), and we only had the one exceptional fossil.

Alright guys, here I come ;) I see Tyrannosaurus averaging 40-43 ft long and 7-8 tons. However, isolated finds and new studies point to max size of 46-50 ft long and perhaps 9 tons or more(maybe as high as 10-12 tons). A recent study shows that Sue, a 42 ft long Rex weighed 8-9 tons at least. As far as pack hunting goes, I see it as fully possible, maybe even likely. Juveniles, faster and more agile, would chase down the prey into the jaws of the larger and stronger, but slower, adults and they would kill the prey. A similar scenario is seen in When Dinosaurs Roamed America and Mammals vs Dinos.

I can see a 45 feet rex, barely. As for pack hunting, I think a small family pack. Kids and parents, and even young adults. Maybe a brother or sister, but nothing else.

yes the 52 foot long specimen is in fact ucmp the 16 year old not the toe the 48 foot long one is actually mor 1126 and mor 1152

Yes, it was 16, and that's almost ten years short of the lifespan of Sue, and it was only slightly smaller than her. But we know Tyrannosaurus had a slow growth rate after about 15. I don't doubt it would have been bigger than her, but not by much. Maybe it would be 43 feet if she was 40 (skeleton axial length).

T-rex grew rapidly from ages 13-18. Then they continued to grow until they died at age 30, but it was much slower. Perhaps they represent male and female animals. Hard to say which is which, but explains why one was bigger than the other. Just a thought.

The T.rex specimen "Sue" is the largest confirmed, and it was 12,3 meters long.