There's nothing quite like the frenetic exuberance of a young dog. Puppies are irresistible in their frantic curiosity about everything that surrounds them, wanting to gulp down all the experiences available to them, just like active, curious children. When they're several years older there's more confidence but just as much activity expressed by active, happy dogs comporting themselves in ways easily understood, conveying sheer love of life.

When Button was young she was irrepressible, and there were times when, through sheer exhilaration, she would suddenly disappear in a swift pandemonium of slender black legs outdistancing us on a nature trail, until suddenly she would back-track and return in a mad trot to us as we ambled along. Sometimes those returns would be accompanied by a demonstration of her attachment to us, when she would gallop along a trail without diminishing speed as she reached us, only to leap into the air so we could catch her midair and clutch her to us, in a return of reciprocal emotional attachment.

Riley, for his part, when he was young, was demonstrably excitable; anyone who might notice him could be assured of his undying devotion. It was all I could manage, at times, to restrain him from leaping into the arms of his admirers. I carried him, back then, inside a small camera case which fitted him quite well, and people would invariably notice him slung over my shoulder. They would ohh, and ahh, and he would respond by taking a flying leap out of the bag into their arms.

Yesterday, walking in the snowy ravine, Riley clumped along wearing his winter coat, but since the temperature had risen to minus-4-degrees Celsius, without his hated boots. Halfway through our circuit a flying ball of fur came whirling along one of the pathways toward us, leaping and snuffling at us, a happy little creature of nature. That little creature, like the squirrels whom we feed peanuts, could smell them in our possession and was frantic to be gifted with a few.

His companion, a middle-aged woman who informed us he was the result of her having thought that the company of a little dog might cheer her and influence her life toward healing after an operation for cancer, said his boundless energy had taken her so aback after she had adopted him from a shelter that she wondered what she'd got herself into. She couldn't bear the thought of returning him there, so persevered, and is now in fine health, and better able to cope with the little dog's antics and as well has recovered a state of mind and physical health to appreciate his joie de vivre.

She allowed him to have the peanuts he craved, and the serious business of extracting peanuts from their shells kept him happily busy for a few seconds of quiet appraisal.