An excerpt from Martin Marten by Brian Doyle (an excellent book by any account):

Background: Martin is a marten living in the wilds of Mt. Hood, Oregon. Some of the book is written from the perspective of the marten, some from the perspective of the main human character, and some from the omniscient narrator’s perspective. In this excerpt, the young marten (Martin) and his sister are growing adolescents and nearing the time when they leave home:

“As July lengthened, Martin and his sister and their mother spent less time together; this was usual and natural and normal, the way of their species for millions of years, but Martin and his sister felt their mother’s attention waning, one bright grain less per day, with some deep sense of. . . what? Sadness, regret, loss, nostalgia? We don’t have good words yet for what animals feel; we hardly have more than wholly inadequate labels for our own tumultuous and complex emotions and senses. It’s wrong to say that animals do not feel what we feel; indeed they may feel far more than we do and in far different emotional shades. Given that their senses are often a hundred times more perceptive than ours, could not their emotional equipment be similarly vast?”