I was thinking deer and fur only exist in tundra. I guess fur can also appear on snow. Now that you mention it I have seen fur on plains but according to the XML that isn't supposed to happen.
Well that happens because tundra gets normalized out as plains.
Are you sure? I thought that the first time I looked but I haven't been able to see that anywhere again. The only thing I see is a check that the food change and the production change are both non-negative.
Oops, you're right. That's what I get for being too hasty in reading the code.
Bh