Those who hunt by night will tell you that the wildest, most vicious of all animals is the tiny shrew.
The shrew feeds only by the dark of night. He must eat his own body weight every few hours or stave to death. The ravenous shrew eats everything, bones, flesh, marrow… everything.
Intro from Attack of the Killer Shrews 1959
Patterns in surnames: There are many ways a surname could have evolved over centuries. One possibility is migration. A Roman name may have traveled to France and hence to England where it was later Anglicized. Case in point - the surname Lawrence went from Laurentius (Roman) to Laurent (French) to Lawrence (English) and then to Lowry (Scottish). There is also natural etymological evolution. For example, a Middle English spelling may have evolved to a modern English spelling (e.g. Stiward to Stewart). Where did your character's Surname come from?