I have just seen a wildlife documentary where eco-tourists out whale watching in Monterey Bay had the experience of a lifetime.

They were on the water hoping to catch a glimpse of migrating grey whales, mostly mothers and calves as they journey along the coast to feeding grounds in the Arctic. Only on this particular day, and for the mother and calf they happened to be watching, the laws of nature were graphically applied.

As the tourists stared on in boats tens of meters from the migrating family a pod of killer whales arrived and began to harass, circle and ram to try and separate the calf from the mother.

This is, of course, what predators do. They predate. Usually on the individual that is easiest to catch or subdue thus giving them a meal that keeps them alive at the lowest risk to their own safety.

On the plains of Africa, lions, wild dogs and hyenas will single out the weakest of the grazing herd – why make things any harder than they already are? Chase down predators, as opposed to those that sit and wait, will benefit from making the chase as easy as possible.

The orcas were persistent. Injuries to the calf steadily accumulated and blood became visible in the water, the reality of the event dawning on the faces of the watchers. For the television audience, the narrator embellishes the visuals with “the calf was being eaten alive”.

Marine scientists, who later analysed footage of the event, observed that it was the younger orcas that took the most active roles in the attack whilst the adult animals held back. “Teaching the youngsters how to hunt”, they concluded – or perhaps leaving the dangerous work to the more agile individuals.

The scientists also concluded that this was “not usual behaviour” or “if it is what orcas do, then we have not observed it” and “maybe it was because of the high numbers of grey whales in the bay at the time”. Or maybe, like the lions, hyenas and wild dogs of Africa, predators rarely pass up an opportunity for lean times are more common than times of plenty.

Whatever the reason, the attack was a prolonged event lasting several hours.

Time enough for the storyline with a happy human ending that is so essential to the modern wildlife movie, as “against all the odds” the grey whales swam towards the shore, reached shallower water and the orcas broke off.

No-one could follow the calf to see if it survived its injuries but the looks on the faces of the tourists interviewed for the documentary left the audience in no doubt. Of course it had survived for the sake of all things decent.

The responses of the eyewitnesses were most intriguing. They went to see nature in the wild where wild things happen by definition, yet they were all shocked, not quite able to accept that wildness includes violence and death. Perhaps if the calf had died quickly and became the meal the orca pod was after the onlookers would have been more accepting of the cycle of life.

Instead, the escape and inevitable pain was, for many, too much. The people were visibly affected.

No doubt a few of them went home to enjoy a t-bone steak.