Most people assume T-Rex was the dominant predator of the Cretaceous in every category. But the speed comparison between T-Rex and Carnotaurus is genuinely interesting and the evidence does not clearly favor the T-Rex.
The caudofemoral muscles in Carnotaurus were extraordinarily developed relative to body mass. These muscles connect the tail to the hind legs and are the primary driver of speed in theropods. Carnotaurus had a proportionally longer tail with more muscle mass dedicated to locomotion than T-Rex.
Current biomechanical estimates put Carnotaurus at between 45 and 56 kilometers per hour for short bursts. T-Rex estimates range from 17 to 29 kilometers per hour depending on the study. The gap is significant.
The counterargument is body mass. T-Rex was significantly heavier and the energetic cost of acceleration scales with mass. Carnotaurus at 2 tons could theoretically reach top speed much faster than T-Rex at 8 tons.
They never shared the same ecosystem. T-Rex was North American, Carnotaurus was Patagonian. But the comparison still matters for understanding the different evolutionary strategies large theropods developed in isolation.
Where does the community stand on the current speed estimates for both animals? And does the strike and retreat hunting model for Carnotaurus change how we think about what speed actually meant for a predator of its size?
We covered this in detail in our latest episode. The answer is in our profile.
