It has been talked to death before, especally around the red deers arival.
Also to make sense of frontiers choices, its less that they have a europe bias here and more that all 5 of europes deer species are just great contenders.
Red deer is arguably THE deer, the fallow deer looks very distinct from the red and is the third most common animal in the EAZA while also seperating itself with its docile nature, most unique antlers of the spotted deers and compatability for walkthroughs and petting zoos, the reindeer is THE tundra animal and the moose is the largest deer.
Even the roe deer makes a great case as a smaller and very common deer with a large range and distinct look, but just for variety sake id strongly prefer a musk deer which comes in the same size class
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