My family and I adopted a puppy in Malawi to serve as our watchdog.

It wasn’t so much that we feared human intruders, but we did fear the snakes and rats that wended their way through the garden where our two children played.

Molly was still a puppy when she killed her first rats and snakes. We’d find the snakes half-shriveled in the sun. The rats we would toss over the gate for the stray dogs to eat, and in the morning, there’d be nothing left.

It was terrifying to me when she killed her first rat — it was an enormous rat and put up a big fight — and Molly cried out a few times, presumably because the rat was scratching and hurting her.

The next day, when I got up, Molly ran to the tree where she’d caught the rat, pointed to the places it had run, and then ran back to me, crying and moaning a little. It was as if she needed to talk about her traumatic experience.

Having grown up in the United States, where my pets were pretty much members of the family and got presents and so forth, I felt awkward ‘using’ a dog for protection.

What if, in the process of saving one of us from some danger, she was hurt? It seemed unkind, somehow, because isn’t a dog’s purpose to sit on a large round cushion from L.L. Bean and look cute?

But Molly isn’t content to do nothing. She likes mental and physical challenges and even needs them to stay healthy and happy. She is devoted to my family and especially to me. I do not doubt she would die for us. But I’m also really glad that, chances are, she’ll never have to.

If we wear leather or eat meat (or eggs or dairy), animals do sacrifice for us. And even if we don’t, animals sacrifice for us. They help scientists develop life-saving medical treatments. And they fight our wars.

When the June issue of National Geographic showed up at my parents’ house this week, the cover evoked my interest and sympathy — and then sorrow.

The cover of the June 2014 National Geographic. Photo courtesy Rachel Marie Stone

Pictured on the cover is Layka, who “saved lives of U.S. troops in Afghanistan after she was shot and gravely wounded.” Inside, another photo showed a tearful soldier carrying the body of Dinomt, a dog who was “killed by an IED while on patrol in Kandahar. His death “spared the lives of nearby soldiers.”

I went outside to throw the ball for my Molly-dog, and to say a prayer of gratitude for the animals who sacrifice for us, and a prayer for peace so that, perhaps one day, they may not have to: that the swords would be turned to plowshares, and the patrol dogs might lie down on huge fluffy pillows, and take a nap.

{If you haven’t heard the story of civilian dog recruits in World War 2, you’ll want to listen to this episode of This American Life.}