The rare sighting of a killer whale mothering a newborn pilot whale is either a touching adoption story or a disturbing case of abduction, says a Dalhousie University researcher.
The couple were spotted swimming together off the coast of West Iceland in August 2021. Researchers say it’s the first time an orca has been documented caring for the offspring of another species.
Elizabeth Zwamborn, a PhD student in biology at Dalhousie in Halifax, was part of the research team that recently published their findings in the Canadian Journal of Zoology.
your conversation with Maritime noon Host Bob Murphy has been condensed and edited for clarity.
You can listen to the full interview here:
What did you see or what did the researchers see when it came to the condition of the calf?
It was what we would classify as emaciated, meaning his layers of fat were not in good condition. Apparently he hadn’t eaten recently, and that doesn’t really surprise us because a killer whale without its own calves probably wouldn’t be able to nurse.
Orcas are often seen in pods. How many were seen in this particular case and perhaps describe how they were positioned in relation to this calf.
This is a group of three known individuals traveling together, most likely a mother and her two offspring, both male and female. But we’re not entirely sure because the studies on the West Icelandic killer whales are fairly recent, only in the last decade or so. What was seen was that this young calf was traveling in what is known as an “echelon” position, or mother-calf position, right next to the female killer whale. That’s indicative of nurturing, because that position, that mother-calf position, is quite taxing for the female killer whale when she’s dragging the newborn with her in her slipstream.
One might assume that this is a beautiful, heartfelt story about altruism and parenting, but actually it could be something else. What do you think?
Well, there are two options. One of them is that she came across this orphaned pilot whale calf that wasn’t doing well, and that’s the story we’re all thinking about, right? This beautiful, heartfelt adoption story. But there’s also a good chance she actually kidnapped that calf from a pod of pilot whales. Off Iceland there has been quite a bit of interaction between the two species and pilot whales are often seen chasing the killer whales. We don’t know the reasons for this, 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.
Is it possible that the calf is easy prey, or maybe they could use the calf to attract other pilot whales?
There it is mainly fish-eating killer whales. They eat a few other things… but mainly this group has been seen foraging for herring… So it is very unlikely that they are trying to attract pilot whales. The other thing is that if the calf was prey, we would. I don’t expect it to be in that mother-calf position that requires energy from this female orca to hold it there, so it didn’t look like a prey situation.
How would the pilot whale calf feed during this time?
It’s a newborn, so very young, probably within a month. And it would need to be taken care of by a person who is capable of taking care of it. So if the killer whale itself had had a calf that was stillborn or died shortly after birth, it might have been able to nurse it. But there’s a chance this female killer whale just can’t reproduce, so if she were to abduct a pilot whale calf, it would be very unlikely she would be able to feed it at all.
If she abducted a pilot whale calf it would be very unlikely that she would be able to feed it anything. – Elizabeth Zwamborn, Dalhousie University
At this point, what’s your best guess as to what you and the team actually saw?
It’s hard to say, of course, if you weren’t there from the start. But this particular female killer whale, Sædís, was observed interacting with pilot whales in a very unique way, where the pilot whales chased the orcas, stopped them, and the orcas then turned back to the pilot whales. And this was repeated several times. So it looked like there might have been an attempt to take another calf. There were newborns in the group.
We know that other species, such as bottlenose dolphins, abduct calves… In fact, there was another case last summer where another female killer whale was seen in the south with a newborn pilot whale calf. So two sightings in two years is quite an eye opener for us and what might be going on between these Pilot Whales and Killer Whales.
I think the biggest thing is that we can’t jump to conclusions right now… We only had this brief interaction with the couple. We are looking for more evidence of this over time or to be able to observe it over a longer period of time.
Do we know what happened to the pilot whale’s calf?
Sædís, the female killer whale, returned again the next year without the calf, so we are fairly certain that given his condition and history of not having calves, it is very likely that he died fairly soon after his sighting.
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