A gorilla at Cincinnati Zoo has been shot dead after a boy fell into his enclosure. When I told my wife, a former vice-director of a zoo, she first asked if the boy was okay and then said how terrible for the keeper who shot the gorilla. I hadn't thought about it from the perspective of the zoo keeper who pulled the trigger. But my wife is right: it must have been a terrible thing for that person, something that may haunt him for the rest of his life.
From this perspective, the case reminds me of the ending of John Steinbeck's novel Of Mice And Men when George has to kill his friend Lennie out of love rather than let Lennie be killed by a lynch mob. Except that Harambe the gorilla, unlike Lennie, had not accidentally killed anyone. Watching the video of Harambe dragging the young boy through the moat was frightening and whether this was done to harm the child or not, it is clear that the boy's injuries could have been far worse.
Yet Harambe was simply doing what any male gorilla would do when confronted with an intruder in his territory. Captive gorillas are trained by their keepers to go to their indoor enclosure on command, but in such an emotionally charged situation, this training does not always work. The two female gorillas responded to the calls of their keepers to go inside, but Harambe did not. When our adrenaline levels are sky high, I'm sure we have all failed to do what we are told.
Previous cases have ended without bloodshed, such as the 1986 incident when a boy fell into the gorilla enclosure at Jersey Zoo in the Channel Islands. The male gorilla, Jambo, famously stood over the unconscious child and protected him, perhaps realising his motionlessness meant he was in distress. The keepers thus took a calculated risk based on their knowledge of Jambo's personality and behaviour, and climbed into the enclosure to rescue the boy.
It is hard to imagine that zoo staff in the US - with its obsession with litigation - would dare enter an enclosure in such a situation.
For me, the big questions concern humans, not gorillas. How was it possible for the child to climb through the enclosure's barrier? This shouldn't have happened, even if the parents were not paying attention. And second, what motivated the child to do this?
What other options did the zoo staff have? In the past, the threat of a dart gun could scare an animal away, or keepers would enter the enclosure with CO2 fire extinguishers. However, these days most zoo animals are trained to comply with veterinary and husbandry procedures, so many won't even recognise a dart gun, while extinguishers are now considered too risky to the health of animals and anyone in the pen with them. So, advances zoos have made through husbandry training mean that some "old" tricks no longer work. "Carrots" have been so effective we've forgotten about the "sticks".
If you're wondering why an instantaneous tranquilliser was not used, the answer is simple: There is no such thing. It takes several minutes for tranquillisers to send a large animal to sleep. Plus, once an animal is very agitated and has massive amounts of adrenaline flowing through its veins, the tranquillising drug may be ineffective. It would be hard to judge the correct dose - too little could result in no effect and too much could result in killing the animal through an overdose. Basically, the zoo is now in a lose-lose situation.
For me, the big questions concern humans, not gorillas. How was it possible for the child to climb through the enclosure's barrier? This shouldn't have happened, even if the parents were not paying attention. And second, what motivated the child to do this? Perhaps he was unable to see the gorillas and his parents did not pick him up to see - so he decided to find a solution to the problem. But zoo enclosures should be designed so that children of all ages and heights can see while standing on their own two feet or sitting in their pushchair.
The situation was tragic for all concerned, but especially for the keeper who shot the gorilla - zoo staff, after all, do their job because they love animals. So this keeper killed Harambe because he felt he had no choice. We can all say "what if" but now is the time to learn the lessons.
• The writer is Professor of Wildlife Conservation at University of Salford, United Kingdom. This article first appeared in theconversation.com, a website of analysis from academics and researchers.