A recently published video of a pod of orcas attacking sperm whales has been getting attention in part because its producers are touting the footage's apparent rarity, and while some have expressed doubt that the footage is rare, the experts seem to agree it is.

Orcas, or killer whales, are the largest apex predators on the planet and the sperm whale is one of the largest animals to be preyed upon, so to see the attack on film is surely exciting.

On his blog at Blue Sphere Media, the documentarian Shawn Heinrichs wrote, "In all my years on the ocean, I had never heard of such a thing and certainly never imagined I would see it with own eyes. We grabbed cameras and fired away as a pod of perhaps 5 Orcas tore into a family of a half a dozen Sperm Whales, right next to our boat! The attack was violent and disturbing as the panicked Sperm Whales were clearly no match for speed and maneuverability of the orcas."

Heinrichs called the footage an underwater world first. But feeling a little skeptical of just how rare an exciting but poorly narrated video of orcas attacking sperm whales really is, National Geographic writer Brian Clark Howard reached out to the experts to fact check the footage.

He reached Robert L. Pitman, a National Geographic grantee and a scientist in the Marine Mammal & Turtle Division of the Southwest Fisheries Science Center in the National Marine Fisheries Service. Pitman studies orca predation and has published two pieces on the topic.

In an email to National Geographic, Pitman said the video is "quite astonishing" and that he has only seen the behavior once before. "It has rarely been observed and never before filmed so I was quite interested in seeing the available footage. This is about the largest predatory event you can witness on our planet - the largest apex predator taking on one of the largest prey species. Truly a battle of titans," Pitman wrote.

Filipa Samarra, another National Geographic grantee, said, "I am not an expert on this particular region, but it seems to me like a very interesting encounter. As far as I know this type of attack on sperm whales specifically is little recorded with such high quality video, but it is known that killer whales may attack sperm whales. This type of behaviour where the group of orcas tries to separate a single, usually young individual, is also known from their attacks on other whales, like grey whales off the California coast."