From Penguin Parade Scans:

Maru, a male marten, became enamoured with the lives of humans, so he transformed into a human and started living among them. Maru's roommate, Sunao, is a quiet and easygoing university student. "Good morning", "Good night", "Let's eat" When they're together, even the mundane is fun... This is a story of the everyday happenings of the two of them living together.