The dinosaur call can be used as a free, albeit less accurate, alternative to the radar, since any animals of the same species as the call being used will answer if they hear the call, even if they are fleeing from the hunter.
Tyrannosaurus produce a terrifying bone-shaking roar when communicating; using the call horn will cause all other dinosaur species to flee in fear, while drawing in Tyrannosaurus from long distances away. This call has the farthest usable range in attracting prey.
Ceratosaurus calls resemble the roar the Tyrannosaurus makes when it gets ready to charge. However, the calls are slightly different. The sound is almost as nightmarish and bone-shaking as the Tyrannosaurus'.
Spinosaurus calls are a strange growl that sounds somewhat like a motor being started up.
Parasaurolophus emit a a loud hollow call that travels a long distance to reach other animals.
Pachycephalosaurus create a quiet low continuous, throaty noise that doen't travel very far.
Stegosaurus calls are deep roars that are similar to the common thought of how a dinosaur roar sounds.
Triceratops emit a low continuous noise that sounds similar to a car engine.