Few New Yorkers have the means — or desire — to follow the example of the late hotelier Leona Helmsley, who left $12 million in her will to establish a trust to care for her beloved Maltese “Trouble.”

But many are taking advantage of a state law allowing them to make more modest bequests for their pets. And that is only one aspect of the rapidly growing field of “animal law” whose practitioners deal with issues that range from cruelty to animals to pet custody disputes.