Perched on the bow of a small boat racing across Puget Sound, Tucker can catch the scent of killer whale scat from as far away as a nautical mile. When he whiffs the slightly salmony smell, the 60-pound Lab leans hard over the bow, so hard that his handler must hang on with all his might to keep him from toppling overboard. The captain points the boat the direction of Tucker’s black nose.

It’s a Tuesday morning. Inside Thompson Hall, in a colorfully decorated basement-level room, a small group of women, each with a Labrador Retriever puppy at her side, sit in a circle. Barbara, a matronly woman with short brown hair and wire-rimmed glasses stands and commands her 16-month-old yellow Lab, Danny, to sit and stay. She then walks out of the circle into an adjacent area set up like an apartment and closes the baby gate behind her. She lies down on the floor as though injured and calls out: “Help! Danny! Help!”