My retired duck & phesant hunting partner.
Barb wire, concertina, shale slides, sheet ice, porcupines, Russian olive thickets, hidden hornet nests, hidden rabbit holes, cliffs, rattle snakes, and lightly wounded aggressive birds could not stop this dog when he was "employed".
In his dotage, on pee break, he trips on a small branch while sniffing for tree squirrels in his own back yard, and blows out his cruciate ligament.