In the eyes of the law, pets are defined as property. Therefore, in divorce cases, a judge's decision about who gets custody of the pet requires no more legal consideration than deciding who gets the barbeque or the Barcalounger.
According to Pet Side Article, some judges have seen an increase in pet related disputes over the last seven years.
In the Midwest, a divorcing couple was clawing over the family felines. The wife claimed the cats ran away, but the suspicious soon-to-be ex-husband hired a private investigator to tail his former love. The investigator captured the woman at home with the cats in question on video. The husband then sued for joint custody in court.
A divorcing duo in Arizona insisted that the judge write into the final orders that along with joint custody of the children, they would also share joint custody of the family cat and all the hamsters.
Check out the article for more info and other resources on break-ups involving the pets.