Kristen and Christopher live right next to the manatees' winter home on the Crystal River in Florida. They come up to them when they're swimming or snorkeling because manatees love people. But people are actually the manatees' greatest threat. Speedboats often hit the creatures and the propeller blades hurt them. Researchers can identify the manatees using these scars. These two friends want to know if these are the same manatees they saw last year?