Chalk up another PR coup for People for the Ethical Treatment of Animals. The animal rights group is grabbing headlines once again — this time with a lawsuit naming five killer whales as plaintiffs, and arguing that the marine mammals deserve the same constitutional protection from "slavery" as people. Are whales really entitled to human rights? Here, a brief guide to this unusual civil rights case:

Who are PETA and the whales suing?
SeaWorld. The whales named in the lawsuit — Tilikum, Katina, Corky, Kasatka, and Ulises — perform at SeaWorld's Orlando and San Diego locations. PETA says that by keeping orcas in captivity, the marine park is violating the U.S. Constitution's 13th Amendment, which abolished slavery and involuntary servitude.

What does SeaWorld say?
Basically, that this is crazy. SeaWorld's attorney, Theodore Shaw, says if PETA were to prevail in what he says is a frivolous lawsuit, the ruling could be used to ruin other marine parks, zoos, and pet businesses. It could even be used to go after pet owners, or even police who use sniffer dogs to detect bombs and drugs. "We're talking about hell unleashed," Shaw says.

Does PETA have a case?
SeaWorld has asked a federal judge to dismiss the case. U.S. District Judge Jeffrey Miller held a one-hour hearing Monday to consider whether the lawsuit — filed by PETA, three marine-mammal experts, and two former SeaWorld trainers — should go any further. Jeffrey Kerr, the lawyer representing the five whales, says even that was a victory. "For the first time in our nation's history," Kerr says, "a federal court heard arguments as to whether living, breathing, feeling beings have rights and can be enslaved simply because they happen to not have been born human." Miller says he'll issue a ruling soon.

Will the judge buy it?
Probably not. During the hearing, Miller told Kerr that he couldn't find a legal precedent for letting humans file a lawsuit on behalf of the whales. The judge also suggested he didn't agree with PETA's argument that SeaWorld is being "hysterical" by saying the case, if successful, could lead to a barrage of lawsuits on behalf of pets and police dogs. "Call me hysterical," Judge Miller said, "but that's one of the first places I went in my thinking about this case."

Sources: BBC News, LA Times, Telegraph