Common bottlenose dolphins, belugas, humpback whales, and other marine mammals are known to engage in the behavior too, according to pre-existing research. In fact, various versions of mothers staying by corpses can seen all across the animal kingdom, from sea otters and manatees to elephants, lemurs, giraffes, and chimpanzees – even when the dead young is in a very advanced state of decay.
There are several explanations for why this happens. In some cases, it has been inferred that it’s a grim form of play rather than of care – something that’s occasionally observed in juvenile common chimpanzees and dead infants – but that’s unlikely in many cases.
It’s noted to occur in species that “rely on cooperation and social bonds”, often involving multiple adults looking after one individual offspring. The mourning behavior, then, may be an extension of the inclination to ensure the survival of relatives.
It’s also highly probable that the mothers are simply incapable of accepting the death of the offspring, something that our own species can certainly empathize with.
The emotional distress aside, J35 seems healthy, and she’s still with her family, but that doesn’t mean everything’s going to get better. Despite the family recently finding some salmon to dine on, J50 – almost certainly the next to die – appears to be starving to death, a clear sign that not all is well.
This relatively small, 75-member strong family of orca whales are, per the Guardian, in danger of dying out. They’ve not had a successful birth in three years, which is why researchers will retrieve the dead calf when J35 lets it go, in order to find out why it didn’t survive.