 Velociraptor plays a major role in the film . The creature 's depiction is not based on the actual dinosaur genus in question , which itself was significantly smaller . Shortly before Jurassic Park 's theatre release , the similar Utahraptor was discovered , though was proven bigger in appearance than the film 's raptors ; this prompted Stan Winston to joke , " We made it , then they discovered it . " For the attack on character Robert Muldoon and some parts of the kitchen scene , the raptors were played by men in suits . Dolphin screams , walruses bellowing , geese hissing , an African crane 's mating call , tortoises mating , and human rasps were mixed to formulate various raptor sounds . Following discoveries made after the film 's release , most paleontologists theorize that dromaeosaurs like Velociraptor and Deinonychus were fully covered with feathers like modern birds . This feature is only included in Jurassic Park III for the male raptors , who are shown with a row of small quills on their heads . 
