Watch VoirFilms. In the Bahamas, more than 30% of dolphins have shark-bite scars. With a never-before-seen non-toxic gel bite pad and life-sized dolphin decoy, Dr. Mike Heithaus and Dr. Valeria Paz collect bite impressions from three shark species that might be the predators. Bites from bull sharks, tiger sharks and great hammerheads — up to 14 feet long — are compared to scars photographed on dolphins.