Controls:

Try changing the parameters for the Predator, Prey and Cage, to see what behaviors develop. (Click the applet before pressing any keys.)

Predator	q: slow down	w: speed up	e: turn slower	r: turn faster
Prey	a: jump slower	s: jump faster	d: jump less far	f: jump further
Cage	z: smaller	x: larger
Other	c: reset all

Source