A 72-foot blue whale washed up on the rocky cliffs of Mendocino County in Northern California (USA) after being struck by a research vessel, the 78-foot Pacific Star. The crew on board was updating maps of the ocean floor for the National Oceanic and Atmospheric Administration (NOAA), moving 5.5 knots seven miles off the coast when the ship shuddered and a blue whale surfaced, bleeding profusely, said Joe Cordaro, a NOAA biologist.

Students from nearby Humbolt State University examined the massive blue whale, hiking down the 30-foot bluff to collect tissue samples. The whale weighted over 50 tons and had, at some point, given birth.

Blue whales are the largest mammals on earth, and researchers determined that the whale had been very healthy and had died from two deep gashes on the back, likely inflicted by the ship’s propeller. The cuts penetrated 9 inches of blubber, then muscle, as well as fragmenting bones.

Researchers said it is rare for blue whales to wash onto shore- they are usually far offshore, deep-water animals.