And so, the killer whale known as J35 is back to her old self. She is no longer carrying the dead body of a calf she held aloft in the water for more than two weeks. Her so-called tour of grief has ended, to the relief of a global audience who had become wrapped up in this heart-wrenching animal drama. Great news, right? Sure. Yet I have a strange feeling in my stomach. It’s a familiar one. The pedant in me is stirring, eager to get us to consider what we know about animals and what we don’t – and may never – know about their lives. It isn’t my aim to belittle J35 and her apparent pain, far from it. It’s rather to make sure we don’t accidentally dilute the emotions of a killer whale by making it all about us.

First, I have form on this issue. A while ago, I published a book called Death on Earth and episodes of apparent animal grief was one of the areas upon which I focused. During my research, I drew up a list of all sorts of anecdotes about animals labelled (by respectable researchers) as evidence of “mourning” and “grief”. These included police dogs pawing at their master’s coffins, macaques resuscitating fallen loved ones and turtles appearing on beaches to mourn at makeshift graves made by humans for the turtles that didn’t make it. I was told by members of the public on Twitter about dogs going off food after losing kennel-mates and horses burying dead stablemates in hay and I was reminded regularly of those BBC documentaries featuring elephants in apparent (but I would argue edited) tears at the loss of a loved one.

So far, so nebulous. Crows added some much-needed science to the field of research into animal grief and mourning. This is because many studies of American corvids (crows, ravens, jays and related birds) have provided repeated evidence that these creatures do behave strangely around the death of their own species. Upon finding a dead corvid corpse, they group together and call wildly with one another, forming a rousing denouement of debate. “Who killed and will they kill again?” they seem to ask one another.

Popular press coverage of this research liked to use the term “funeral” to describe these gatherings. This bothered me a little. Is there ritualisation similar to what you would see at a human funeral when crows and jays gather like this? Is there mass grief and sadness like that at most human funerals? No, of course not. And there’s definitely no necrophilia at human funerals either. Yet, many people think crows understand death in a way that we have no evidence they do. Why? Because of the human words we use.

Facebook Twitter Pinterest ‘J35 is no longer carrying the dead body of a calf she held aloft in the water for more than two weeks.’ Photograph: AP

But killer whales are thought of differently. Like us, they are highly developed social mammals with an impressive language, dialects and even cultures. J35 must have been mourning, we think. She simply must have been. The problem is there is no way (yet) to scientifically test for sure that this is the case. Even with all the photos, there is still a distinct possibility that J35 may have just been confused. She may have even hoped her baby would revive. Pedantic (and blunt) as it sounds, if you believe J35 was displaying evidence of mourning or grief, you are making a case that rests on faith not on scientific endeavour, and that makes me uncomfortable as a scientist.

This might seem unreasonable and even brutally cruel to some readers but remember this behaviour has been documented only a handful of times and that, on the whole, the sea is not filled with killer whales displaying such extreme and dramatic behaviours each time a loved one dies. Compare that to human societies, all of whom undergo dramatic periods of social upheaval upon the death of friends or family. You are likely to have experienced it. You, the reader, may still be carrying the effect of death in your human heart. That’s actual grief. That’s actual mourning.

The killing of a blue whale reveals how disconnected we are from nature | Philip Hoare Read more

Am I being a pedant? Probably. But by loosely labelling these emotions willy-nilly in animals, I worry that we make two mistakes. The first is that we squeeze a whole range of animal behaviours into discrete categories of human emotion, thereby overlooking and failing to celebrate their unique brand of animal majesty. The second is that we dilute a real, powerful and observable human emotion by granting other animals the same emotions so freely without any scientific rigour.

When we hold up a magnifying glass to nature, it’s all too easy to see ourselves reflected in the frame. Yet to truly know animals takes a more polished lens and a more measured use of words. We may never know if killer whales experience a sadness quite like our own (they may even experience a pain we cannot imagine) but a key point remains: regardless of whether they have the same emotions as us or not, they deserve our utmost kindness and our respect. Just like everything else.

• Jules Howard is a zoologist and author