In the first known case of this type, a female orca appeared to adopt a baby pilot whale.
In 2021, scientists observed the orca tending to the calf in western Iceland, according to a new study.
The study found that the orca had never had a calf of its own.
A female orca appears to have adopted or abducted a baby pilot whale in the first known case of its kind, scientists say.
The orca known as “Sædís” was first spotted swimming with the pilot whale calf in August 2021 in western Iceland.
Scientists observed that Sædís not only accompanied the calf, but actively took care of it.
Two other orcas, likely from the Sædís pod, were also present, but no other pilot whales were seen – which is unusual given that pilot whales also travel in pods.
This is the first scientific documentation of killer whales tending and caring for a longfinned pilot whale calf.
The findings, recently published in the Canadian Journal of Zoology, document the orca’s maternal care for a pilot whale calf and suggest that the relationship between the two species is more complex than previously thought.
Marie Mrusczok, the lead author, told Newsweek that there were clear signs the orca was caring for the calf.
“The orca was swimming with the pilot whale’s calf in the relay position, which means the calf was swimming just behind the orca’s pectoral fin,” she said.
“The echelon position allows a calf to make fewer caudal movements than when swimming alone, and to overcome physical limitations during high-speed travel – in other words, the calf is ‘carried’ by the pressure wave created by the adult’s larger body . “
However, Elizabeth Zwamborn, a scientist on the research team, told Canadian Broadcasting Corporation’s Maritime Noon Show it was unclear whether the adoption was an altruistic one.
She said the relationship could be interpreted as a “beautiful, heartfelt adoption story” or a case of a killer whale abduction.
“But there’s also a good chance she actually abducted that calf from a pod of pilot whales. There was quite a bit of interaction between the two species off Iceland, and pilot whales are often seen chasing the orca,” she said.
“We don’t know why, but if there’s a chance that there’s a female orca here and there trying to take a calf from the pilot whales, that would certainly be a reason to hunt them down.”
The study found that Sædís had never had a calf of her own, so it’s possible she took the pilot whale calf as a surrogate.
Zwamborn said the calf appeared to be emaciated and hadn’t been fed recently, which would make sense as the orca female would likely be unable to nurse since she hadn’t given birth to any calves of her own.
Both killer whales and pilot whales have similar close family structures in the wild, which could explain the relationship.
About a year later, Sædís was spotted with a group of long-finned pilot whales, but the calf was not present. Further encounters between Sædís and the pod of pilot whales indicated a deliberate attempt to acquire a new calf, the findings said.
Zwamborn told CBC that Sædí’s observed interactions with pilot whales appeared to be unique and that she may have attempted to kidnap another calf.
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