Standard walking speeds do not scale with size.
Watch a squirrel. When it wants of cover terrain, rather than foraging, it bounds at a rapid pace, often with quick stops, then more bounding. They virtually never walk at a constant modest speed. Same for other small ground mammals, it is documented in the literature. Partly anti-predator tactic. But it also saves energy. Cost of animal ground locomotion at a given body mass is about the same per unit distance regardless of speed. But walking slowly means expending more energy via the basal metabolism that is constantly ticking, relative to the distance covered, again is in the literature. And walking slowly wastes time not accomplishing any tasks, so do it faster while burning less watts.
Ungulates small and big commonly walk at around 3 mph. As do elephants. I can do 12 miles in 4 hours on the C&O canal towpath. In my teens once did 50 miles on the C&O in 20 hours straight, but that included stops for BF and lunch. 3 mph would have been the normal speed of sauropods up to the biggest. Watching super sauropods would have looked strange. With their long strides they would have had low stride frequency, so they would have looked like they were in slow motion even when walking at the same speed as an elephant -- this is similar to how jumbo jets near the ground seem to be flying more slowly than say a 707, which I first realized in 1970 watching a 747 approach Dulles, it takes longer for them to cover their own length (one of the Being engineers watching the prototype 747 was scared it was going to crash when making its first landing because it seemed to be flying too slowly). Interestingly trackways seem to record somewhat higher average speeds for theropods as per the graph in my Complete Dinosaurs chapter, but that is iffy. Reptiles walk much more slowly, just don't have the aerobic capacity to sustain such high speeds, even the most energetic and biggest monitors.
3 mph for adult tyrannosaurs may be a little on the slow side, but is not unreasonable.
-----Original Message-----
From: Dann Pigdon <dannj@alphalink.com.au>
To: DML <dinosaur-l@usc.edu>
Sent: Wed, Apr 21, 2021 8:00 pm
Subject: Re: [dinosaur] Tyrannosaurus rex walking speed (free pdf)
On Thu, Apr 22nd, 2021 at 7:14 AM, Mike Taylor <
sauropoda@gmail.com> wrote:
> 1.28 m/s is a bit less than 3 mph, which is a reasonable human walking
> speed. Is it credible to imagine a T. rex walking alongside a human at the
> same speed? I'm not sure it is. It would require either very short strides
> or a very slow stride time. Perhaps this finding fails the "smell test". Or
> perhaps I am just using an Argument From Personal Incredulity.
It would be interesting to see how this predicted preferred walking speed scaled allometrically throughout
a tyrannosaur's life.
Keep in mind that the preferred walking speed isn't the same as the maximum walking speed. It may
have just been the most energy efficient speed for moving long distances.
--
Dann Pigdon