It’s not every day you see an alligator and a bull shark swimming in unison together, but that’s exactly what Florida resident Gray Vinson witnessed while visiting Indian River Lagoon.  The Vero Beach native, who grew up swimming and boating around the river, says he filmed the rare moment from a walking bridge.   He says bull sharks and gators have been spotted before but to my knowledge this is the first time together. Video shows both creatures gliding next to each other in the brackish water. Vinson also captured a video of a manatee that appeared to escape the shark and gator unscathed.  The Indian River Lagoon is a bull shark nursery, according to the University of Florida. Young bull sharks typically use the area until they are about 9 years old, and then move into an adult habitat offshore.  Vinson says the area is well-known for seasonal bull sharks.