Greyhounds have long been the focus of controversy. In Shakespearean England, they were the favored dogs of Queen Elizabeth I. She decreed that only nobles and royalty could own the breed. Her wily subjects evaded the ban by crossbreeding greyhounds with other canine varieties to produce the lurcher, which wasn’t technically a breed and was therefore exempt. More than 400 years later, one of my best friends is a lurcher.

His name is Sid. He isn’t my dog, but he stays with me whenever his owner is away. Last year he had an additional, unexpected three-week sojourn at my house. He came to me to recuperate after being knocked down by a car.

At the same time that Sid was tentatively hobbling around my home, a modern greyhound controversy was culminating in Massachusetts. After months of bitter debate, a ban on greyhound racing came into force. The state’s tracks were closed; the industry was shut down.

There are strong animal welfare arguments against greyhound racing, including claims that the dogs are sometimes kept in cramped cages. Occasionally, horrific injuries sustained during races require the afflicted animal to be euthanized at the trackside. Plus, racing careers are short (greyhounds typically retire at the age of 3 or 4), and the dogs face the prospect of being destroyed on retirement.

Ironically, animal welfare had been one of the motives behind the creation of formal greyhound racing in the 1920s. Prior to the establishment of dedicated tracks, greyhounds had been bred for coursing, a betting sport in which the dogs chased and killed live quarry, including jackrabbits, deer and coyotes. With the invention of an artificial hare that could mechanically zip around an oval track, coursing was reinvented as a blue-collar alternative to horse racing.

In the United States, the sport reached its peak in the mid- to late-20th century. At its height, an estimated 3.5 million people bet nearly $3.5 billion on 16,827 races. Since then, opposition and competition from other forms of gambling have contributed to its decline. Today, the greyhound racing industry is a shadow of its former self.

Even so, regular races are still run in many states, and thousands of dogs continue to be bred for racing. Not all campaigners are calling for a total ban. For some, the issue is not the racing but what happens to the dogs when they can no longer compete. Organizations such as Greyhound Pets of America aim to provide loving homes for the retired racers, with some success. The Greyhound Racing Association of America claims that 90 percent of registered dogs are either adopted as pets or are used for breeding purposes on retirement.

Sid has never been anything other than a pet. In common with his greyhound relatives, he combines a docile, friendly disposition with an innate hunting instinct. One morning while I was walking him across fields, he chased and caught a deer. Both animals tumbled to the ground and looked at each other in shock. Sid then took fright and ran back to me while the unharmed deer cantered away to safety.

In the days following his car accident, which had left him with an injured hind leg, Sid struggled to contain the urge to unleash his talent for speed. Time and again he attempted to sprint around the garden, only to pull up, yelping with pain. As his leg began to heal, he was able to sprint full laps of the perimeter, even though he was clearly limping when he finished. He couldn’t resist the impulse. His prime purpose in life is to run.