A US federal judge may rule on whether animals enjoy the constitutional protections against slavery as human beings. The case — to test the 13th Amendment to the US Constitution, which prohibits slavery — arises from a move by Sea World to dismiss a lawsuit filed by People for the Ethical Treatment of Animals (PETA) that names five orcas (killer whales) as plaintiffs, CNN reported. Three marine-mammal experts and two former orca (killer whale) trainers have joined PETA in claiming that the captured orcas are treated like slaves, forced to live in tanks and perform daily at Sea World parks...