Stags are some of the inhabitants of the Coal Creek Zone, a militaristic area led by said stags. These people were known to be war-like and oppressive, beating down the weasel population and making them work in the mines. At some point, Nack the Weasel bribed The General to overthrow his stag peers and help the weasel become ruler of the Zone. Many other stags still live in the Zone, the majority that have been seen work as guards. Others seem to be terrified of the Freedom Fighters, perhaps taught to fear them.
Before this, they were seen as an individual tribe living during the time of Bravehog. Unlike the rough and ready stags of today, old-time stags were seen to be posh and unable to tolerate other tribes. Upon hearing about King Leer's conquest over the badger people, the stags believed it served them right, being "primitive" with their filthy claws "from all the digging they do". They also believed that, due to their status, the hyenas would not touch them. They soon learned that the hyenas didn't care who they overrode. Because of their unfriendly nature, they did not aid Bravehog and other species in the final fight against their oppressors. They may actually have been the extinct Irish Elk, to be specific.
Deer, generally the female version of a stag, very rarely appear as background characters on Mobius. One such deer employed Tom Manx to sweep her chimney, mow the lawn and re-tile her bathroom.