For more than 60 years, a strange phenomenon has plagued a small town in Scotland: pet dogs leaping to their death off the same four-story bridge. In the last six months alone, five dogs have perished. Now, we join a leading animal behaviorist to determine what is causing man's best friend to commit suicide. Then, Florida Fish and Wildlife agents are investigating the mysterious deaths of several manatee. Could the cause be natural, or is a human hand to blame?