Zeke, a white and gray short-haired cat with a penchant for taking down rats, is known in his Boston neighborhood as a fearless prowler. Once, a neighbor called his owner, Tricia Brennan, sounding slightly panicked. “‘Zeke is in the back and seems to be antagonizing a raccoon,’” the neighbor said, according to Ms. Brennan, a Unitarian Universalist minister. “‘What do I do?’” The showdown ended whe