Some starving zombies survive

[readerboy7]

Is there a way to have some zombies survive, even once they've killed all the humans in the country? For example, I'd like to make a symptom that allows a number of zombies to survive by eating wildlife. say,

Code:

max(1000, (country_population/(1000*population_density))) * 2 if rural, *.5 if urban

Is this possible, and if so, how?

[AnimalMan]

Country Bonus Decay rate?