There seems to be a LOT of controversy over how fast
Tyrannosaurus was capable of running. Some researchers argue that an adult tyrannosaur couldn’t run (that one foot always had to be on the ground), and that it was limited to a top speed of 11 miles per hour. Most estimates of
Tyrannosaurus rex’s top speed fall between 11 and 25 miles per hour, depending on the researcher’s views. I have also heard that it has been estimated that it would have taken an adult
T. rex one to two seconds to make a 45? turn. (In other words, if you ever find yourself running from a tyrannosaur, zigzag.
)
The shape and proportions of tyrannosaur leg and foot bones (particularly the shins and metatarsals) suggest that they were actually some of the swiftest runners among dinosaurs their size; better adapted for running than other large theropods. In fact, the limbs and feet of juveniles and small species were very similar to those of similarly sized ornithomimosaurs (“ostrich dinosaurs”; the group that contains “egg stealers”). Seeing as the two groups evolved alongside one another, it has been suggested that they developed their running adaptations in response to one another, the ornithomimosaurs becoming faster in order to better escape tyrannosaurs, and the tyrannosaurs becoming faster to more easily catch ornithomimosaurs. So juvenile
T. rex, at least, may have been one of the fastest dinosaurs. I saw a profile for a 21-foot-long juvenile
Tyrannosaurus specimen nicknamed “Jane” that gave 20–30 mph as a possible top speed, but I don’t know how scientific this figure is. Still, I think you’d be okay with having your adolescent Blackclaw running at 30 or even 40 mph (though this is in no way a scientific assertion).
The problem is, if a full-sized
T. rex tripped and fell while running at high speed, it could severely injure or even kill itself. (The sharpteeth in LBT are unrealistically durable.
) So even if large tyrannosaurs
could run at high speeds, they probably didn’t do it very often. Furthermore, while it is not known exactly how large
T. rex’s leg muscles were, it has been argued that they were not sufficient to power high-speed running. One study concluded that for an adult
T. rex to run faster than 25 mph, it would need to have an impossible proportion of its muscle massó86%óconcentrated in its legs, and that its top speed could not have been more than 11 or 12 mph (though the study has been accused of overestimating
Tyrannosaurus’s weight, and not taking into account how its musculature differed from that of the living animals used to validate the mathematical model on which its conclusions were based). Another study from 2007 came up with a figure of 18 mph as the top speed for
T. rex. To tell you the truth, it’s all so confusing to me that even
I don’t know what to believe.
In any case, an adult
Tyrannosaurus was probably faster than any of the large herbivores it shared its habitat with (it has been argued that ceratopsians like
Triceratops could run at rhino-like speeds, but that’s a discussion for another time), though a recent study suggests that the majority of its diet consisted of young dinosaurs that it could swallow whole. And, if all else failed, a big
T. rex could always steal a kill from a smaller one.
As far as your story is concerned, it
is about a sharptooth who can scale a cliff or a longneck’s back in a single jump, and survive falling hundreds of feet, so you can probably get away with having him run at unrealistic speeds
(40 mph or so). However, if you want to be more realistic, 12–20 miles per hour would probably be safer.
As for the skin thickness of
Tyrannosaurus, I can’t tell you much, but it certainly was no armor plating, and wouldn’t have stopped the horn of a
Triceratops or the teeth of another tyrannosaur. As to exactly how thick it was, though, I have no idea. A few tyrannosaur skin impressions are known, and they show that their scales were small, round, raised, and arranged in “symmetrical rows” (read that in an article; not entirely sure what it means
). One small tyrannosaur from early Cretaceous China,
Dilong, is known to have been covered in filamentous “protofeathers”, which opens the possibility that some or all tyrannosaurs were at least partially feathered at some point in their lives.
Hope this helps, and thank you for the question.
