Using phenomenal paleoartwork by Nobumichi Tamura, host Hank Green of the PBS series Eons explains exactly why Tyrannosaurus Rex had such tiny arms and how they evolved to the point where they really didn’t need arms at all.
The characteristics we think of as defining T-Rex namely a huge head and tiny forelimbs were actually part of a 90 million year trend in that direction. And that big head wasn’t just for looks, its enormous jaws gave T-Rex bite force up to 57,000 Newton’s which is enough to pulverize bone with a bite. Having long four limbs wasn’t really necessary but beyond that long arms weren’t just not needed for some dinosaurs they were kind of in the way.
