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.

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.