Could you summarize for us a couple of the major ways that keeping animals as pets gives you pause?

The pet industry encourages people to buy pets, and the way animals are advertised and sold gives the impression that pet keeping is easy and fun. You can buy an animal for less than you can buy a new pair of shoes. And this makes it easy to underestimate the seriousness of the decision to bring an animal into our homes, and feeds into an attitude that animals are disposable.

My aim in writing Run, Spot, Run is to reinforce the fact that pet keeping involves taking responsibility for the life and well-being of a sentient creature, and giving an animal what he or she really needs is challenging and shouldn't be taken lightly. I also, perhaps even more importantly, want to raise awareness about the broader implications of the pet industry, for animals.

For example, now that I know the "backstory" on the reptiles and amphibians sold in many pet stores (the dismal conditions in which animals are "manufactured" — bred, transported and housed — before they arrive on the shelves, and the extremely high mortality rates), I would never buy a gecko from a big box pet store. The cost to the animals is just too high.

As you've just noted, it's not just cats and dogs you're talking about in the book.

No, in fact, I'm much less concerned about dogs and cats than I am other species of animal people keep as pets. I worry about exotics and wild animals, because their physical and psychological needs are extremely difficult to meet in a home environment. And I worry about animals who must live their entire lives in a cage or tank.

When kept alone in a small cage, birds, small mammals like hamsters and gerbils, and even fish lack adequate physical, mental, and social stimulation. Solitary confinement of human prisoners is considered a violation of basic human rights, yet this is essentially what we do to some of our pet animals. It just seems unfair to impose this on them, for the sake of our curiosity or entertainment.

I was surprised at your statement in the book that "Cats and captivity present, in my view, one of the most vexing pet-keeping conundrums." Why is this? Our six indoor cats seem to us very content: They enjoy sun patches, toys and bird-watching out the window, but, even more, the dual-species social dynamics of the eight of us in the house keep them thinking hard, and well-occupied. And they're not outdoors killing birds and small mammals.

I think the indoor/outdoor cat issue is vexing because we can't just go by a single rule or principle — because all cats are different, and each cat's home environment is different. Furthermore, both indoor and outdoor options have important downsides. What I find problematic are the hard-and-fast declarations such as "all cats must be kept indoors" or "all cats need to be outdoors."

It sounds like your cats have a wonderful life, and being indoors seems to be working really well for them and for you. I know a lot of other cats who have really good indoor lives and who seem quite content. But I also know cats who need more space to roam, who have a wandering spirit. Lots of cats are going crazy inside, if you go by reports of high numbers of behavioral issues and health problems such as obesity.