So, I have mammoth as a resource in one of my cities. Unfortunately, it is quite low down on the map. According to what I have researched, to get to the point where I can create Mammoth riders I am going to need a mammoth trainer (which makes sense). It's telling me that the mammoth trainer needs to be at a certain latitude, which would be much higher than this current city. But the mammoth trainer can only be built in a city with mammoths. So, am I in an unfortunate catch-22 situation or is there a way for me to relocate my mammoths to a higher city?