Just outside Ruaha National Park, a wildlife-rich reserve at the center of Tanzania, government rangers train working dogs—Jenny, a Belgian Malinois (pictured above), and Dexter, an English springer spaniel (below)—to sniff out concealed ivory that might otherwise slip through the cracks.

Dexter is two and, befitting his breed, full of energy, according to his handlers. Jenny, also two and extremely intelligent, comes from a line of working dogs. Her two brothers are currently with police units in the United Kingdom.

According to Claire Bracebridge, a technical advisor for WCS Tanzania, dogs like these are becoming an increasingly important tool in the fight against illegal wildlife trafficking.

Watching them do drills, it's clear why. A mock checkpoint is set up and Jenny and Dexter, together with their handlers, take turns inspecting a car for stashed ivory.

The dogs are eager, as they have been trained to associate the scent of ivory with a reward, usually playtime with a ball. In this case, each whiffs ivory by the wheel well, sits, as trained, and looks at his/her handler to indicate its exact location. As promised, they get their prize for a job well done.

Written by WCS's Julie Larsen Maher. Read more about the dogs on our photo blog, Wild View.