Despite their fame as movie stars and entertainers, orca whales were first and foremost known as the "wolves of the sea." After all, they aren't called "killer" whales just for fun. Recently, scientists from the NOAA were reminded of this after coming upon a gruesome scene, where a pod of orcas absolutely decimated their prey until there was little left. Some forensic sleuthing has now revealed just what the victim was, and it came as something of a surprise.

NOAA Fisheries marine mammal survey observers came upon the "murder scene" in question some 200 miles off the coast of Central California. The orca attack was still going on when they were a few miles away, and the observers were able to watch the gory scene unfold through sets of high-powered binoculars. The victim of this attack was visible, but they couldn't make out what it was between thrashing tails and sprays of reddened seawater.

By the time the waves - slick with oil and blood - settled, the orcas were long gone, but they hadn't cleaned their plate. The lungs and heart of the victim remained floating on the surface, and that was more than enough material for scientists to determine what it had been.

"We didn't know what that animal was," researcher Brittany Hancock-Hanser said in a statement. "But given the capacity of our lab and how much work we've done on cetaceans (whales, dolphins etc.), we knew we had a pretty good chance of figuring that out."

The NOAA's Southwest Fisheries Science Center houses one of the largest collections of tissue and DNA samples from marine mammals and sea turtles in the world. An estimated 175,000 tissue samples from roughly 145,000 unique animals can be found in giant freezers there, providing valuable DNA information that can be used to match to new samples, like the evidence collected.

A computer analysis of DNA from the lung sample was launched, looking at a specific portion of the DNA that is known to distinguish various marine mammals. After a little over a week, the results were in, revealing that the orcas had feasted on a pygmy sperm whale - a species never before documented as killer whale prey.

It's unclear what exactly sparked this whale-on-whale predation, but while uncommon, it's not unheard of. Type-A killer whales in the Antarctic are known to prey on small minke whales, even while other sub-species of orca prefer fish, seals, and penguins.

"We weren't able to get there soon enough to see just what was going on," Hancock-Hanser added. "But through genetics we could piece together what happened and learn something new from the result."

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