Well, with the theory (granted it's just a theory, but it is widely accepted and rather hard to debate in some cases) of evolution the strong survive and continue on, thus the deer found today would be much more hardy, smart and disease resistant than those found years ago. Each winter the weaker deer will perish and the stronger will continue on, soooo each year the strongest will survive. Also, in the case of deforestation and other anthropogenic changes, the deer that are better able to adapt will survive. If you were to take a deer from 250 years ago, it would probably not survive very well today due to resistances that have been built up over time to certain disesases and other things along that line. So saying that deer are the same now as they were in their creation? that's rather hard to support IMO