Vet ethics: Painlessly killing versus herbivorising predators

Some philosophers interested in animal ethics have lately been turning their attention to the problem of wild animal suffering. Most of us would agree that we have duties to prevent or limit suffering in animals under our care. But do we have similar duties to animals in the wild? 

This is a controversial idea. Yet some philosophers think it deserves greater consideration. After all, suffering is, in itself, bad. It would seem callous to simply ignore it. And nature is, unfortunately, rife with suffering. 

In significant part, this is due to predators. Predators cause both severe physical pain and significant distress and anxiety to their prey. As one philosopher writes:

Bears and wolves will sometimes start eating an animal who is still alive and conscious. Hyenas disembowel their living prey. Pythons squeeze their prey to death. Orcas will chase mother whales with calves until the mother collapses from exhaustion, so that she can no longer protect her calf, whose tongue they like to eat. Chimpanzees tear live monkeys and bushbabies apart. Crocodiles dismember their prey while rotating them underwater in a death roll.

The philosopher Ben Bramble considers some ways we might reduce this suffering. He asks whether it might be right to (a) genetically engineer predators so that they can live on plant foods (i.e., to “herbivorise” predators); or (b) painlessly kill predators to spare their prey the severe suffering.

Bramble argues that painlessly killing predators might be morally preferable to genetically herbivorsing them.  At first sight, Bramble’s ideas may appear too extreme—even to those who think suffering is a deeply unfortunate fact of nature. However, Bramble produces some arguments to back them up. 

Bramble does acknowledge that intervening in these ways could have large negative effects. For example, without predators, there may be explosions in prey populations and damage to ecosystems. 

On the other hand, this is an empirical question and must be approached on a case-by-case basis. For example, if a particular kind of predator was already in relatively low numbers (e.g., tigers), and the ecosystems had somewhat adapted, then removing such predation might not significantly damage those ecosystems. 

Even if now is not the time to carry out the removal or alteration of predators in some fashion, it might be more feasible in the future, Bramble suggests. For instance, biotechnology might advance to the point where it is possible to genetically alter bears, dingoes, crocodiles, and lions so that they survive on non-meat diets.

Bramble considers and rejects the idea that a decrease in human enjoyment resulting from the absence of (non-herbivorised) predators could outweigh the benefits of reduced suffering among prey animals. Humans could still enjoy watching predators in films and documentaries. 

Virtual reality, which produces more realistic images of the marvels of predator appearance and behaviour, could also facilitate this enjoyment. Furthermore, we could gain satisfaction from knowing that prey animals are not suffering at the hands (and teeth and claws) of predators.

So, there seems to at least be some reason for contemplating removing predators either by painlessly killing them or by herbivorising them through genetic engineering (perhaps through CRISPR or some other technology). 

But why does Bramble think painlessly killing predators might be morally more justified than genetically herbivorising them? As he acknowledges, this seems counterintuitive, given that the predators would lose their lives. Losing a life, he says, is a major harm.

Nonetheless, Bramble argues that painlessly killing predators would immediately benefit all the prey that would have suffered from being predated. This would be a large number of animals, since each predator can kill many prey animals. 

Bramble then argues that because the alternative of genetically modifying predators would take some time, the prey those predator species come into contact with will conceive their offspring at different times than they otherwise would have. 

This means that the offspring would not be the same individuals as they would have been had the intervention not occurred. Therefore, these prey individuals necessarily do not benefit from the genetic intervention. (In philosophy, this is called the ‘non-identity’ problem.)

Furthermore, argues Bramble, the genetically herbivorised predators might suffer from not being able to hunt or to teach their offspring to hunt. This could potentially affect their relationships with their offspring and make them confused or depressed.  

Perhaps we will be able to find holes or flaws in this sort of argument. Bramble himself admits that killing predators is not easy to justify. What is clear, though, is that some thinkers are taking more seriously our duties to animals in the wild. 

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