Mausvolk

Mausvolk can sustain themselves with mere water and leafy green vegetables.  Some Mausvolk have even become omnivorous while others are strictly carnivores.

Mausvolk live in large groups together, either as nomads or in their own out of the way communities.  A gathering may very well be all of a single family or multiple families.

Mausvolk often have a somewhat above average intelligence.  They make excellent chemists and spellcasters.  However, being the product of magic tends to dissuade many from pursuing arcane or occult knowledge.  Those who do are often outcasts from their communities or their families.

The first Mausvolk were an experiment by the mages of old.  Wizards of the Transfiguration school desired reliable servants without the ties that conjuring a familiar would bring.  Mice were selected because they exhibited the ability to think critically and solve basic problems.  These mice were magically imbued with augmented intelligence and often given the ability to speak.  It wouldn't be fore decades that they would be enlarged and begin to walk upright.
Realizing that they were slaves to the whims of wizards, when the opportunity to join the revolt arose they took it.  They were instrumental in overthrowing the masters of the Transfiguration school.  When the Mage War ended they were free to roam and settle where they wished.  Despite the help the Mausvolk gave, many of the other races saw them as magical abominations and shunned their existence.  It was the will of the new world leaders that they should be allowed to exist.
Mausvolk spread far and wide, typically keeping within their own tight knit communities.

Mausvolk are looked down upon even today.  The term "Ratfolk" being bandied as an insult to them, despite some of them actually being rats.  Mausvolk are cautious of any species that is typically larger than themselves.