The synthetic ecosystem has now been running for over a day. Sor far, the most successful tiger has managed to propogate its "genes" for seven generations. The most successful cow has only propogated its genes for three generations. Nothing goes extinct because I guarantee a minimum population, but so far, these creatures cannot survive on their own. Watching cows charge tigers makes this clear.
I'm also thinking that I'll have to convert the app to Tk. I've been trying to make it a console only app that can run on any operating system, but it's proven more difficult than I thought. I think Tk will solve these problems. Too bad I don't know Tk (yet)