‘Extraordinary’ sighting of killer whale with baby pilot whale astounds scientists

Killer whales, or killer whales, are apex predators, best known for their ferocious hunting techniques. So when a female was seen seemingly caring for the offspring of another species, it came as a surprise. “I immediately saw that something strange was going on,” says Thérèse Mrusczok, who worked as a spotter on the Láki Tours whale watching boat that witnessed the encounter.

The ship’s crew initially thought it was a very small orca calf swimming alongside the killer whale, but photos later confirmed what Mrusczok suspected: that the female, named Sædís, appeared to be caring for a newborn long-finned pilot whale.

The unique sighting occurred near Snæfellsnes, in western Iceland, in August 2021, and is now the subject of a research article published in the Canadian Journal of Zoology. “It’s another level of empathy that we see in these animals when they are able to care for another species,” said Mrusczok, president of the nonprofit organization Orca Guardians Iceland and a researcher at the West Iceland Nature Research Center.

The question researchers have been unable to answer is whether the calf was adopted after being orphaned or abandoned, or whether Sædís stole the calf from its parents. “There are many possibilities … but what we can say for sure is that the female acted protectively towards the pilot whale calf,” says Mrusczok.

The newborn was seen swimming alongside the orca in the “drafting” position, meaning it was swept along by her and required less energy to swim. It is not known whether the calf’s attraction was mutual, or how long their intercourse lasted.

The pair were seen swimming together for 21 minutes and were joined by two other adults — a female named Dragonfly and a male named Zale, who are often together as a group. Dragonfly and Zale tolerated the calf, but it is not known if or how they dealt with it directly.

An orca swims with her own calf in Norwegian waters

An orca swims with her own calf in Norwegian waters. Photo: Cavan Images/Alamy

Killer whales and pilot whales have similar social structures and form strong, long-lasting bonds between mother and offspring, so researchers believe interspecies care could be a possibility. Although the calf was emaciated, it appeared that it was being cared for by the killer whale.

Sædís has never had any offspring of her own in the nine years that researchers have followed her, so it is unlikely she produced any milk that would have sustained the calf.

One theory is that the killer whale may have miscarried or lost a newborn just before this encounter, and could have provided replacement for the pilot whale calf, although there is no evidence to support this.

Watching killer whales has taught me that there is always mystery, that there is always more to discover

Thérèse Mrusczok, researcher

Groups of killer whales and pilot whales are known to chase and antagonize each other. Researchers think they do this because they compete for resources – in Iceland probably Atlantic herring or mackerel.

In 2022, researchers saw something else they hadn’t seen before: pilot whales returning after being chased away. They did this three times. The researchers wrote in the paper: “It is possible that the movements of the killer whale group as a whole may have been influenced by an active effort by SN0540. [Sædís] to get another pilot whale calf.”

Rob Lott of Whale and Dolphin Conservation, who was not involved in the study, says: “These creatures spend most of their lives underwater, out of sight and often far out to sea, so perhaps this extraordinary encounter is not so unusual . But what’s exciting is that it’s the first time it’s been documented.

“If it was a kidnapping or abduction, it might go some way to explaining why long-finned pilot whales often chase away groups of killer whales.”

Related: Agony on a Cornish beach: what do whale strandings tell us about our oceans?

While this is the first time this behavior, called interspecific alloparenting, has been observed in killer whales, it has also been observed in other cetacean species. Common short-beaked dolphins, bottlenose dolphins, Indian Ocean humpback whales, and Indian Ocean humpback whales have all been observed caring for the young of other species.

Mrusczok says: “Anything is possible – watching killer whales has taught me that I never know what will happen. There is always mystery, there is always more to discover.”

Sædís was spotted interacting with long-finned pilot whales again in 2022, but the calf was no longer with her and it is believed to have died.

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