The Gardeners' Gopher Problem

My gardener friends complain endlessly about gophers eating and damaging their plants. They also recount their histories of tactics to defeat the furry little geniuses, all failures.

My thought: Build a small robot to wander the gopher tunnels, detecting and eliminating the furry little geniuses. Perhaps deploy a number of such robots per plot, each at different tunnel location, to cover all escape routes.

Seems to me if one can build a robot to vacuum one's carpets, one should have little trouble building one to solve the gopher problem.

Research and imagination needed for design specifications.