Lots of potential, love the idea. I do feel like Grass -> Rabbit -> Wolf -> Repeat + as many Wolfs as possible is too easy to get and very strong. but adding other creatures to lower the chance of getting heaps of Wolfs, or more dynamic interaction would fix this. 

Lots of Lag when getting a large circle and no zooming makes it hard to place once the you get too zoomed out. 

Great Demo!