National Geographic on Instagram: "Whale watchers in Madeira captured the astonishing moment orcas took down a pygmy sperm whale. According to newly published research, they may have documented the first known instance of orcas hunting a marine mammal in Madeira, a Portuguese island territory. The remarkable sighting gives scientists a new example of orcas’ complex predator behavior and raises concerns that they might prey on some of the region’s endangered marine mammals. Learn more about what