[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: New Velociraptorine



Good day all,

Russ Anderson wrote:

>99% of the time...  the sickle claw is out of the way [i.e. retracted]
>and stays sharp. 

        Really? Ever since Bakker's restoration of Deinonychus back in the
60's it has been unanimously assumed that all "sicle-clawed" theropods, such
as dromaeosaurs and troodontids (I have even seen a restoration of
Ornitholestes with such a digital gesticulation!), held their "killing
claws" clear above ground. This is based on the assumtion that this would
keep the claws sharp. However, I object to this mode of restoration for
several resons.
        First, several living birds have modified toe claws to suit various
tasks. Herons have bizzare comb-like medial claws that they use for
preening. Cassowaries and rheas have toe claws that they often use for
combat, much in the same manner that is postulated for dromaeosaurs. I have
even read an account of a rhea killing an Australian boy by slashing his
throat with one such claw. No bird that I know of carries any of its digits
aloft, but that rhea's claws were sharp enough to kill the kid none the less
(although tenontosaur hid would no doubt be something more substantial)!
        Second, and perhaps more importantly, I know of no distinct,
irrefutable didactyl theropod tracks. Period. 
        Third, the wear experienced by normal locomotion would have been
miniscule compared to repeated contact with bone while dispatching prey (if
the claw were even used in this role at all). There would have been no need
to hold it aloft to reduce wear (the claws may have even been
self-sharpening, like those of a cat, for all I know). 
        Fourth, I do not know of any articulated theropod feet that show any
evidence of a retracted claw. This probably doesn't provide a good
indicator, after all the animals had died and dried, but negative evidence
beats no evidence at all.
        As for the claw's function: IMHO, I doubt that the claws were even
used as a weapon for killing prey. The troodontids, for example, were just
too light to effectivly make use of such weaponry. The bigger ones, like
Utahraptor, could be better expected to utilize thier tremendous mass to
better employ the claw to penetrate and tear.
        I contend that the claw was for mating battles between males (I
belive that Deinonychus has two distinct claw morphs; one with larger claws,
see GSP's PDW), with a climbing role secondary. Ever been to a cock fight?
The advantage of such an apparatus is clearly apparent, and selective
pressures would lean heavily towards the better armed individual in this
scenario. 
        The skulls of dromaeosaurids were perfectly good for most
carnivourous endeavours. They could have brought down large prey when they
were in packs using their teeth alone, like cape hunting dogs, but small
prey were also probably very important. I know that this will make a lot of
people mad, but I think they did a lot of scavenging too.
        Incedentally- the photos of the "fighting speciment" from Mongolia
that I have seen show the feet of the Velociraptor a fair distance from the
Protoceratops, but I would'nt trust this alone. Does the Protoceratops have
any claw-slashed ribs? Just wondering. 
        That's my two cents, and if in the event anyone agrees with me I'd
love to hear from them.

--Sam Girouard

sampaula@pacificrim.net