Dogs, cats, and other pets do have feelings, but it's often useful to interpret their feelings in the context of their worlds, not ours.

If you've watched a dog while its family was away on vacation before, you probably noticed the pet was subdued --and sometimes even looked depressed and lonely, jumping on their family, barking, and wagging their tail manically when they were reunited. Studies have shown that canines are capable of experiencing a wide range of emotions-- in a similar manner to the feelings humans experience, giving whole new meaning to the moniker "man's best friend". It is normal to feel that pet companions are sympathetic; you'd like them to be when you vent to them at the end of a stressful day. Cats are notoriously jealous of new kittens added to the family, or a new baby, often taking a considerable amount of time to adjust to the change in family structure, much in the same way that a child with a new step-parent might. So how can we know what emotions pets feel, and what feelings they don't? The answer is, of course, we can't because we can't ask them... but we can observe them and compare our findings.

Charles Darwin concluded that there is an emotional and cognitive continuum between animals and humans, and that animals experience the same range of emotions, just not the same degree. A dog may get anxious simply because it can't find its toy, whereas a man may get anxious when his wife's flight is delayed, which might make him late for his meeting. It's the same emotion, just a different degree of it. So before you think Goldie the Goldfish is just a invertebrate swimming circles in her fishbowl consider this: a 2007 Canadian study indicated fish may even have their own distinct personalities, making a bowl full of fish possibly as diverse as a room full of preschoolers.

Jane Goodall's work with primate research found that primates have highly developed capabilities for empathy, forming strong bonds of attachment, and mourning within their highly complex social systems. When Goodall trained Koko the Gorilla, she taught her 1, 000 words in American Sign Language and, upon the accidental death of Koko's beloved kitten All Ball, Koko communicated the signs "cry" and "sad" to her trainers, adding more evidence to the fact that animals, in fact, do experience emotions, even if the range of them is shorter.