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Re: Varanus komodoensis feeding



Nice! I heard rumblings of this one for a while. Glad to see it is finally out. 


Jason

 
http://reptilis.net 


"I am impressed by the fact that we know less about many modern [reptile] types 
than we do of many fossil groups." - Alfred S. Romer


----- Original Message -----
> From: "Thomas R. Holtz, Jr." <tholtz@umd.edu>
> To: 'DML List' <dinosaur@usc.edu>
> Cc: 
> Sent: Thursday, 20 October 2011 5:41 PM
> Subject: Varanus komodoensis feeding
> 
> http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0026226
> 
> D'Amore DC, Moreno K, McHenry CR, Wroe S (2011) The Effects of Biting and 
> Pulling on the Forces Generated during Feeding in the
> Komodo Dragon (Varanus komodoensis). PLoS ONE 6(10): e26226. 
> doi:10.1371/journal.pone.0026226
> 
> Abstract
> 
> In addition to biting, it has been speculated that the forces resulting from 
> pulling on food items may also contribute to feeding
> success in carnivorous vertebrates. We present an in vivo analysis of both 
> bite 
> and pulling forces in Varanus komodoensis, the
> Komodo dragon, to determine how they contribute to feeding behavior. 
> Observations of cranial modeling and behavior suggest that V.
> komodoensis feeds using bite force supplemented by pulling in the 
> caudal/ventrocaudal direction. We tested these observations using
> force gauges/transducers to measure biting and pulling forces. Maximum bite 
> force correlates with both body mass and total body
> length, likely due to increased muscle mass. Individuals showed consistent 
> behaviors when biting, including the typical
> medial-caudal head rotation. Pull force correlates best with total body 
> length, 
> longer limbs and larger postcranial motions. None of
> these forces correlated well with head dimensions. When pulling, V. 
> komodoensis 
> use neck and limb movements that are associated with
> increased caudal and ventral oriented force. Measured bite force in Varanus 
> komodoensis is similar to several previous estimations
> based on 3D models, but is low for its body mass rela
ull force, especially in the ventrocaudal
> direction, would allow individuals to hunt and deflesh with high success 
> without 
> the need of strong jaw adductors. In future
> studies, pull forces need to be considered for a complete understanding of 
> vertebrate carnivore feeding dynamics.
> 
> -----
> 
>> From the Conclusions:
> 
> lthough the V. komodoensis behavior model is unique amongst extant taxa, it 
> can 
> shed light upon the feeding behaviors of extinct
> ziphodont tetrapods, especially theropods [34], [47]. Supposedly some 
> theropods 
> also had relatively low bite forces given their size
> and cranial morphology [1]. As in V. komodoensis, such low bite forces may 
> have 
> been supplemented by a strong pull and would not
> hinder the animal's ability to modify flesh. Both tooth mark data and 
> cranial morphometrics suggest that theropods used caudally
> oriented force during feeding [47]-[49]. Modeled neck musculature implies 
> that 
> some theropods (i.e. Ceratosaurus and Allosaurus)
> also displayed significant ventroflexion, suggesting the "pulling" or 
> "raking" of ziphodont teeth through the use of these
> postcranial muscles [50].
> 
> Thomas R. Holtz, Jr.
> Email: tholtz@umd.edu    Phone: 301-405-4084
> Office: Centreville 1216            
> Senior Lecturer, Vertebrate Paleontology
> Dept. of Geology, University of Maryland
> http://www.geol.umd.edu/~tholtz/
> Fax: 301-314-9661        
> 
> Faculty Director, Science & Global Change Program, College Park Scholars
> http://www.geol.umd.edu/sgc
> Fax: 301-314-9843
> 
> Mailing Address:    Thomas R. Holtz, Jr.
>             Department of Geology
>             Building 237, Room 1117
>             University of Maryland
>             College Park, MD 20742 USA
>