Scientists observe male orca kill calf in first-of-its-kind discovery

Scientists discover killer whales engage in infanticide, just like many other mammal species. (Reuters)

Researchers in Vancouver said they observed a first-of-its-kind discovery when they witnessed a male killer whale drown a baby killer whale.

Three researchers were documenting a pod of killers whales off the coast of Vancouver Island in December 2016 when they heard a noise and saw “erratic movements,” The Washington Post reported.

"We got a little closer and realized that the baby whale we observed earlier wasn't surfacing," Jared Towers, a cetacean researcher with Fisheries and Oceans Canada, told the paper.

Shortly after, a male orca was seen with the baby “hanging out of its mouth,” in what Towers described as a 'first of its kind' kind of observation."

The male orca proceeded to drown the calf, as its mother tried frantically to save it. At one point, the mother rammed the other orca with such force, "blood and water" splashed into the air.

Towers, Muriel Halle and Gary Sutton had their findings published in March in the journal Scientific Reports.

The discovery indicates killer whales also engage in infanticide, a behavior found in primates, rodents and in some cases dolphins, the report stated.

Infanticide is frequently a “behavior that leads to sexual behavior," which is what Towers said he believes to be the case for the male orca drowning the baby. The male, he theorized, attempt to mate with the mother.

The mother of the older male whale also got involved in the skirmish, trying to protect her son. And after about 20 minutes, the chaotic scene came to a close.

"I think it may be because the mother realized the calf was dead, so what was the point of continuing to fight after that?" Towers said.

It’s unclear whether any mating occurred between the male and the mother afterward, but Towers said they would be able to tell if she has another baby soon that matches the male orca’s genetic material.

"Looking at the behavior we've observed, we're now beginning to think that it's quite possible that females don't have a lot of choice when it comes to breeding," Towers told Canadian Broadcasting Corp. News.