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Re: Could Tyrannosaurus Rex jump?



Asking for a friend. What's the consensus? Has anyone tried to tackle this
question?


It is not too difficult to do a back-of-the-envelope estimate of this. 
According to our paper

Gatesy, Stephen M., Martin Bäker, and John R. Hutchinson. "Constraint-based 
exclusion of limb poses for reconstructing theropod dinosaur locomotion." Journal of 
Vertebrate Paleontology 29.2 (2009): 535-544.

you can expect a max. force of a single T. rex leg of about 1.5 body
mass. You get this when the leg is still fairly straight, bent about
50cm or so compared to a fully stretched leg. So if you assume for
simplicity that the force is constant throughout (this is an
overestimate), with a single leg you could get enough energy to jump
75cm high; perhaps a bit more if you do some tricks with your tail, ot
if you bend down further (but too much bending is not possible).

Jumping with both legs wuld roughly double this.

So overall, a jump of 1meter or a bit more seems realistic, but since
the T. rex could overcome that height difference with a simple step,
there's probably no need to run.

In general, it should also be taken into account that a simple scaling
estimate shows that all animals should jump to roughly the same
height: muscle force scales as area (with length of animal squared),
the energy is force multiplied by length, so total energy is
proportional to l**3, as is mass. Using the potential energy equation
W=m g h, the l**3-term cancels out.

(Of course special adaptations can change this simple picture. Please
also note that jumping height is always to be calculated relaive to
the position of the center of mass - a human jumping over a 2m bar
raises her center of mass only by a bit more than a meter.)

Hope this helps a bit,

Martin.

                   Priv.-Doz. Dr. Martin Bäker
                   Institut für Werkstoffe
                   Technische Universität Braunschweig
                   Langer Kamp 8
                   38106 Braunschweig
                   Germany
                   Tel.: 00-49-531-391-3065
                   Fax   00-49-531-391-3058
                   e-mail <martin.baeker@tu-bs.de>
                   
http://www.tu-braunschweig.de/ifw/institut/mitarbeiter/roesler1
                   http://www.scienceblogs.de/hier-wohnen-drachen