Type 'debugon' while playing to enable debug mode. In this mode dinosaurs will ignore your presence until you shoot. Also you have unlimited ammo in debug mode and lava does not kill you.

 

In debug mode:
Ctrl - makes you run REALLY fast.
Shift + S - switches on/off slow mode.
Shift + T - switches on/off timer indicating polygons per frame and time
used to render this frame (in milliseconds).