Mice are the decendants of the ship's evolved lab mice or mus sapiens.
Based on Red Dwarf Roleplay Book
Mice are generally short and spry in their youth, eventually becoming more rotund as they age. Though they retain their mouse like appearance they have evolved to walk on two legs and use their hands to operate machines and pubs. Mice do wear clothing and take pride in owning objects.
Mice have very sharp sences and can quickly hide when danger is nearby.
Though the Mice have their own language of chatter that is common to them, they have also learned to speak English. In fact they have also learned many of the bad social habits found in a pub.
More social and gregarious than their rat cousins, mice are organized into a tightly knit social hierarchy and tend to be attracted to group settings. Mice are attracted to shiny objects and sweets, and aren't happy unless they have their own "nest" - some private place with comfortable bedding and plenty of hidey-holes for their stash.
Mice have no real religious background since they are greedy and materialistic creatures.
Mice are the decendants of the ship's evolved lab mice or mus sapiens and have set up shops all along the Blue Dwarf's Promenade. The shops offer a variety of services such as dinning, pubs, game centers, clothing repair, trinket repair and resale shops. The mice didn't keep very good history on their race since survival was their first concern untill they were able to get a strong hold on the ships trade center. Once the mice were established they had a strong period of growth before the crew began to awaken.