Dogs
This is old news. I think, however, that some factors are ignored in stories like this one. Dogs and humans have cooperated not just practically but emotionally, and one reason for this is the relative ease of communication between the two species. Dogs are adept at learning a number of words. Furthermore, dogs express themselves in ways that humans find easy to understand. If my dog, Lucy, is lying down, and I say her name, I can hear her tail thumping the floor in response. When she is appreciative, she licks my hand (even right after I have washed it.) She is an unusually expressive dog, showing joy by wagging her tail, wagging her head, and skipping around the house at a speed and in a fashion that would be ruinous given her size, were it not that she is amazingly agile. She has been, so far, incorrigible and hyperactive to a point where a few minutes with her can be exhausting, but she improves, and we love her dearly. We have two adorable and affectionate cats, Persians, but there is something special about a dog, the way one fits in, the easy affinites. As soon as I finished school and had a place to live with room, I got a dog, two, in fact, and I have had dogs pretty much continuously since then and loved them lavishly and mourned their passings, deaths which I think of often and which bring me to tears, still. And, I am nowhere near my first youth, and my midlife crisis, if I ever had one, is a memory faded and blurred by many years. As long as I can, however, I want to have a dog, one to greet me in the morning, one I can give love to simply by feeding it, one I can love. Protecting the house is in second place, and by a large margin.