Form and Function

Velociraptor mongoliensis was a small non-avian, feathered theropod dinosaur that grew to be about 24 kilograms, or roughly the size of a wild turkey.  As eluded to on our homepage, V. mongoliensis was a dinosaur of disproportionate characteristics that helped make it an efficient and devastating predator.  Its “killer” claws and other skeletal features made for one terrifying dinosaur.

The “Killer” Claws

Velociraptor mongoliensis possessed three sickle claws.  The abnormally large middle claw could be extended and rotated 180 degrees at the theropod’s will.  There are multiple ideas about the functionality of these claws.  The original hypothesis is that the claws were used for disemboweling prey, however, currently there are many paleontologists that disagree with this idea.  For example, Fowler et. al from the Museum of the Rockies and Department of Earth Sciences point out that there are several living species of birds and non-avian reptiles that possess similarly adapted sickle-claws. These extant species instead make use of their claws for grasping and holding down prey which provides good evidence that V. mongoliensis possibly used their claws for the latter as well  (Fowler et. al. 2011, Manning. 2006.).  The most widely accepted hypothesis is that V. mongoliensis used its claw to pierce the throat of its prey.  The sickle shape of the claw, with a sharp point and smooth, curved underside, provides insight that while the claw would have been good at piercing thick flesh, it would have been insufficient for easy ripping and disemboweling actions (Carpenter. 1998, Fowler et. al. 2011.).  The greatest evidence for this hypothesis is the fossil specimens of “The Fighting Pair.” 

Skeletal Features

Velociraptor mongoliensis had a longitudinal ridge dorsal to a row of neurovascular foramina in the maxilla of the skull. The skull had a concave upper surface and convex lower surface which created long, slender, upturned snout.  These characteristics make V. mongoliensis easy to identify from other Dromaeosaurs that otherwise look similar in skull structure.  Like other Dromaeosaurs, V. mongoliensis had a mouth full of sharp, backwardly-serrated teeth that were great for tearing through the flesh of its prey.  Its skull was attached to a large S-shaped neck and spine which continued into a long, stiff tail which was disproportionate to rest of the dinosaur’s body length (Hone et al. 2012).  The long tail length was advantageous for this predatory dinosaur in that V. mongoliensis could use it like a rudder for steering and balance while chasing prey, much like the modern day cheetah (http://bioweb.uwlax.edu/bio203/s2007/marek_davi/). (Hone et al. 2012, Public Broadcasting Station. 2014).

Here is a video showing this mechanisim in action.

Velociraptor mongoliensis had a pelvis with a characteristic pubis that pointed downward and forward at an angle toward the ischium.  The acetabulum of V. mongoliensis opened dorsolaterally, indicating that it could abduct and adduct its hind limbs.  This morphological characteristic demonstrates that the ancestors of V. mongoliensis were probably capable of flight and therefore the flightlessness of Velociraptor was secondarily lost (Longrich and Currie. 2009).  
Feathers are modified scales, so it should come as no surprise that some dinosaurs were feathered. Evidence for this is supported by the quill knobs found on the posterior forearm of V. mongoliensis indicate that the dinosaur was feathered.  While V. mongoliensis certainly did not make use of its feathers for flight, it is hypothesized that the small theropod used its plumage as a means of display to attract mates and to cover its nest to protect its eggs.  It is also possible that V. mongoliensis used it’s feathered arms while running uphill to create a negative lift, accelerating their bodies upwards and forwards allowing for a faster paced run up inclines (Turner et. al. 2007). In combination, all of these characteristics made V. mongoliensis a very efficient and lethal predator.

For reproductive information on Velociraptor, have a chat with Dr. Eric Snively or see our page!