When a marriage ends in divorce, it's the custody of the kids that's hardest to settle. But a growing number of ex-couples are also battling over another member of the family - the dog.

"I tell attorneys who are handling divorces, number one, ask if they have kids. Number two, ask if they have pets," said Debra Hamilton, a New York mediator, according to Reuters. "These days, pets are just as important as kids. Sometimes even more important."

A survey done by the American Academy of Matrimonial Lawyers (AAML) last year showed at least 27 percent of pet custody cases have been filed in the last five years. Among these, 88 percent were custody cases for dogs, while 5 percent were for cats. The remaining number were for other pet animals, including snakes, turtles and iguanas.

"While pet custody cases are not an everyday occurrence, far too many spouses attempt to initiate these disputes as a negotiating strategy, often believing that they can use the animal as a kind of bargaining chip. This tactic is usually not effective and can come back to 'bite' the antagonist throughout the divorce process," Maria Cognetti, president of the AAML, said in its report.  "When it comes to a pet, it is often obvious which of the spouses has the strongest emotional bond."

Experts say that the rise in pet custody cases may be attributed to the number of couples choosing to have pets instead of children, which are treated like their own children. But for couples who do have kids and pets, the lawyers stated that the pets stay where the children stay in most cases.

Apart from the custody battle, ex-couples also have to negotiate over money issues in raising the dogs.

"I call it 'doggy support,'" said Jacqueline Newman, an attorney in Manhattan, who shared the story of one client with a very expensive dog, Reuters reported. "High vet bills, special food, doggie daycare, dog walkers. It was more than $1,000 a month."

The cost of raising dogs can average between $2,674 to $3,536 annually, and $23,410 in a lifetime, according to the American Kennel Club.