Tyrannosaurus’ Tiny Arms
From movies like, Meet the Robinsons, to many internet sites, the T. rex’s short arms provide comic relief. The relatively short arms (I say relative, because although they look laughably short on a T. rex body, they were actually still 3 feet long) make one wonder how they functioned for this ferocious predator.
It’s still a mystery for scientists and wide-eyed children alike.
- For mating: the tiny arms were used by males to grasp females during copulation
- For eating: the small arms could be used to hold prey while the T. rex ate the animal
- For pushing itself off the ground in case the animal ever fell over (not an easy thing to do when you weigh 9 tons!)
A recent paper by Snively et.al. suggests they didn’t need their arms for feeding. This group of scientists studied reconstructions of the T. rex neck and studied the feeding habits of existing relatives of the T. rex, modern raptors such as hawks and eagles. These birds feed by tearing into their prey with their mouths, pulling upward and shaking their heads. Snively et. al. mapped the musculature necessary for the feeding behavior and found similar muscles in the T. rex neck. This would suggest that T. rex arms were not required for feeding.
We were anxious to check out the T. rex for ourselves yesterday at the Natural History Museum. Unfortunately we should have done our own research beforehand. The museum is working on setting up a new exhibit with one of the most complete T. rex fossils ever found. Beginning in 2019, the Smithsonian Natural History Museum will display an 80-85% complete T. rex fossil (short arms and all) found in eastern Montana in 1988. Right now scientists are studying and documenting each individual bone before assembling the 65 million year old puzzle.
Until then, we will have to be content with our memories of the T. rex fossil in Chicago.
Blogging my way from A to Z as part of the 2014 April A to Z Challenge!