Okay, I'm slowly getting a picture here. This
isn't grasping the way I normally think of grasping (opposable thumb etc),
it's more like a pair of pliers or mole-grips. Does the immobility
of the hand and it's size tell us anything about the prey it was going after
*** Although there may be others on this list who
won't agree, I think the association between Deinonychus / Tenontosaurus
material speaks for itself. I think they hunted Tenontosaurs in groups
and scavenged carcasses when the opportunity presented itself. If you want to
draw an analogy ( I know many won't) with modern African cats hunting a
variety of larger herbivorous quadrupeds, in spite of differences is size
differential between predator and prey yadda yadda yadda. . . in either case
the smaller predators are more than willing to risk potential injury in favor
of securing a meal. Whether they selected injured animals, juveniles or
just went with a pack hunting, bloodlust mentality, Tenontosaurs were likely
choice victims on the dromaeosaur menu (pers. comm. Bob Bakker). Maybe
they rushed in, inflicting deep wounds / disembowling the target animal and
then followed at a safe distance until the victim died of shock / bled to
death. Dinosaurs are not mammals obviously, nor were they brittle
skeletal remains that have a propensity to fracture into a thousand pieces
when dropped on hard museum collections floors ( and no, I haven't done that
either). In life, I'm sure they were capable of handling the stress
factors involved in predation, scavenging, clepto-parasitic backhanded (now
you see it, now I steal it ) parlour tricks (ala Tom Holtz DML archives )or
any other strategy necessary to play on the "Survival of the
Fittest" gameboard ( action figures and batteries not included )
as attested to by their lengthy proliferation recorded
within fossilbearing strata.
Seems to me our poor, much abused cat would be
better grasped with a smaller, bendier hand whereas the dienonychus' manus
would be better suited to larger prey?
*** Alternate scenario. . . In order to capture
smaller, swift and agile prey, Deinonychus thrusts its hands forward
temporarily enclosing the prey, pins it to the ground with pedal digit 2
ungual and dispatches victim with snapping jaws.
Also, is it possible to tell if these adaptations
were evolved for prey capture or if they were later exaptions (is that the
right word?) from Archie-type wings?
*** 10 paleontologists - 10 hypotheses with
David Marjanovic wrote: . As I cited, "As with
most extant predators, the mouth was used to grasp the prey. Then the short,
powerful arms were used to grasp or clutch the prey against the body to
prevent its escape while the teeth were disengaged and repeated bites made to
kill the prey."
*** Or. . . Tyrannosaurs may NOT have used
their forelimbs in securing live prey, period. and evidence of trauma in
postcrania including arms, hindlimbs and ribcage could simply be a result of
thrashing prey animals responding to crushing jaws. OR by intraspecific
ritualistic bump and grind between two rival adult theropods. OR by clumsy
utilization of basic motor skills ( too busy eyeing up the blue plate special,
accidently stumbles into large innocuous tree trunk / humans manage to do it
all the time, what's their excuse). I have a hard time imagining a
tyrannosaur being able to grasp with any degree of leverage, the bulky girth
of any struggling adult ornithopod!
Sorry if I seem to be labouring this point, but
I'm still having trouble with it. While I'm not disputing that it is
physically possible, why is it better to do this rather than deliver a big
bite and back off? As I understand it, theropods can't take falls and knocks
the way for example big cats can. So why risk grappling with prey about as
heavy as they were?
*** That would SEEM to be a more practical means
of dispatching prey when you consider large strong jaws / reinforced
skull, puncturing teeth, sizable neck musculature all support a bite, twist
and tear scenario, leaving the victim momentarily disoriented, traumatized,
mangled and eventually weakened from blood loss, awaiting the inevitable
end. PROVE IT? Don't have to. . . that's the province of
paleontologists. I just get to paint it ;o) !