Roco was the dog that inspired me to create dog portraits.

One thing that happens when you walk a dog is that you meet other dogs. You learn each one's name, age, breed, temperament and where it came from. After many meetings, you notice what the dog's human looks like, and eventually you learn the human's name.

We met Roco and his human, Jim, in just this way.

At our first meeting, we stopped to inspect Roco, talk about him, pet him and give him a treat. We learned that Jim had found Roco wandering through the neighborhood, apparently lost. 'I don't know a lot about dogs,' Jim says, 'but I like to walk them.' So he walked Roco home and tried to find the owner.

Over the next year, Jim consulted with various professionals to make sure there was no bite behind Roco's ferocious-sounding bark. He took Roco for daily walks, and we began carrying treats with us on our walks. Roco snuffled them out of our hands as gently as if he had no teeth at all.

Roco died in January 2009. He didn't seem like himself one day, so Jim took him to the vet. He had tumors, the vet said, and one of them had ruptued his spleen. It was the sort of thing that couldn't be fixed.

All of us who met Roco were sad about losing him. And it also made us realize how important it is to just like walking dogs. He had a great last year.