The first version of creatures was my attempt to learn something new, and naturally contained messy and unstructured code.  I have attempt to rewrite a cleaner version, and add some controllability.  In the new version, a predator can be selected and it will follow the mouse rather than follow the nearest prey.

creatures_controllable

 

This new version is more efficient, and can handle more creatures.  The prey also look more sophisticated.  I added some code so that the page looks okay when loaded on a web browser, after learning how meta tags should be used when designing web apps.