As the expression "nature red in tooth and claw" suggests, there is an cruel inevitability to life and death in the animal world.
So quite what a Welsh animal lover was thinking when he tried to rescue a tiny duckling that had just been eaten by a heron is open to question, the Daily Telegraph reports.
More puzzling still is the fact that to save it from its natural fate he cut open the heron and pulled the terrified duckling from its stomach.
The effect was, rather predictably, to kill the heron, although the duckling survived relatively unscathed.
North Wales police arrested the elderly man but released him with a caution.
North Wales Police's Rural Crime Unit described the man on Twitter as "vulnerable and elderly", without revealing the name of the culprit or when and where it took place.
Officers said "a male was cautioned for killing a heron", adding: "He had witnessed it eating a newly born duckling so decided to kill the heron in order to rescue the duckling from its stomach.
"Strangely he actually did rescue the duckling alive from the dead heron's stomach. But obviously he was then left with a dead heron. You couldn't make this up!"
Some people criticised the police decision to let the man off with a caution.
The heron is a protected species under the Wildlife and Countryside Act 1981, and anyone killing or trying to kill one faces fines or prison.
Lee Dingain, a conservationist and trustee with the Wader Quest shorebird charity, said: "Utterly ridiculous! Not too elderly to kill an apparently 'protected' and not to mention formidable bird. The heron is the vulnerable one! Decisions like this are a major part of the reason why wildlife crime is not taken seriously. If he had stabbed someone he would be prosecuted."
Jane Kennedy, who describes herself on Twitter as "passionate about wildlife", added: "Clearly a protected bird has been illegally killed on this occasion, so a crime has been committed."
The police said: "These decisions are never taken lightly and a number of factors are addressed. This was a vulnerable elderly man, who confessed voluntarily to the action with no previous convictions."