@insideedition: Marine biologist Tom Hird's search for the world's largest great white #shark is featured during Discovery's "Shark Week," hosted by #JohnCena. They're looking for a 6,000-pound shark. Also on "#SharkWeek," prepare for an alien invasion. Wildlife biologist Forrest Galante searched for a rarely seen and little-known species of sharks. Cameras captured a rare velvet dogfish shark giving birth.