I enjoyed serving this essay up for you, and I did it for free. But I am currently out of work, and a bit of revenue would gladden my heart. Think of it as a voluntary subscription. And, yes, you can use that as a testimonial if it helps. My first reaction to questions like this, is to snicker and belittle them.
Dogs are an immutable form.
Their very essence is their unchangingness. But this one got me going. Dogs are not really faithful, in the sense of never changing. The oldest breeds, like the mastiff and greyhound, are only a few thousand years old. All the rest were created in the last couple of centuries.