Scientists have observed a behavior never before seen in killer whales, and it makes for a grim discovery. Following strange calls from orcas off the northeastern coast of British Columbia's Vancouver Island in December, researchers observed the first known case of infanticide among the whales. After tracking down the orcas and hearing a ruckus in the water, the scientists spotted a male orca with a newborn calf in its mouth, being chased by the calf's mother and other members of its family. As the male's mother attempted to intervene, the calf's mother "hit the male so hard that ... his blubber was shaking on his body and you could see blood flying through the air," ecologist Jared Towers tells the CBC. "We were really quite horrified and fascinated."
The male still didn't let go of the calf, which had died by that point, according to Newsweek. Researchers, describing the case in Scientific Reports, say the male orca likely killed the calf so the male orca could mate with the infant's mother. In other mammals, infanticide "forces the infant's mom into a fertile state much quicker," Towers says. He adds researchers previously thought female orcas were picky about mates, but this behavior suggests "females don't have a lot of choice when it comes to breeding." The CBC notes $9 million the Canadian government has dedicated to orca research may reveal more about the endangered species in time, as Washington state works on protection, per Time. (Orca pregnancies are failing.)