Do orcas mourn their dead?
News of an orca apparently grieving for her dead calf hit the headlines this summer, but can we say she was mourning?
IN LATE JULY, an orca known as Tahlequah – part of the endangered Southern Community group that mainly lives in Puget Sound and off the south coast of Vancouver Island – gave birth to a calf. Sadly, the calf died, but the mother nonetheless carried it around with her for at least 17 days. News reports suggested that she was grieving for her dead baby, but can we really understand what was going on in her mind?
“We know that orcas have large brains and are social, so this kind of behaviour does not surprise me,” says Erich Hoyt, a research fellow for the UK charity, Whale and Dolphin Conservation, who once witnessed similar behaviour in a female Pacific white-sided dolphin. “Orcas are heavily invested in their young, and they remain with their mothers for life.”
Hoyt points to a 2017 study by another cetacean researcher, Giovanni Bearzi, which examined 45 cases of cetaceans showing caring behaviour towards dead or dying animals – in most cases individuals of their own species. The paper notes that, where a species invests a lot in its relationships, then grief is the cost or trade-off of that commitment.
When apparently grieving behaviour is witnessed, continues Hoyt, it demonstrates “that an individual is in trouble and the mother wants to help, but it doesn’t prove actual grief.” The idea that whales and dolphins have developed culture – orcas in their idiosyncratic feeding behaviours, for example – is widely accepted, but “the question is have they developed culture around death?” asks Hoyt.
As Bearzi points out, some examples of behaviour interpreted as mourning could be something entirely different – a male short-finned pilot whale carrying a calf in its mouth could have come after it killed the juvenile, possibly as a way to mate with its mother.
The real tragedy in this case, observes Hoyt, is that the Southern Community that Tahlequah belongs to is declining, with an estimated three- quarters of all newborns failing to survive during the past two decades and its population dropping from nearly 100 to 75 over the same time period.
We know that orcas have large brains and are social, so this kind of behaviour does not surprise me