An Analysis of Lethal Methods of Wildlife Population Control

In the field of wild animal suffering research, there are many variables to consider, not the least of which is simply measuring the phenomenon at all. What’s more, even in situations wherein wild animal suffering can be quantified and measured, that doesn’t mean it will be reflected in policy and management. These two papers, from the Wild Animal Suffering Research repository, analyze lethal methods of wild animal population control; one among vertebrates, the other among invertebrates. The analysis goes further, however, and considers non-lethal methods too.

As a rough estimate, the paper notes that at least 25 million vertebrates are killed each year as part of population control, through a variety of methods. These methods of population control might “cause more suffering than natural causes of death”, although detailed research would be needed to check this, and this is not necessarily always true.

Nevertheless, to the astute advocate, it seems likely that there are more humane methods of population control, such as immunocontraceptives and genetic modification. These methods may even reduce animal suffering compared to if there were no population control interventions at all. This is because they might prevent animal populations from reaching their environmental limit, which often leads to starvation and “immense suffering”. Both of these methods are, however, untested on large scales, and so more resources and research are needed to make sure that they can work.

From there, the paper offers an insight into population dynamics and culling methods, providing estimates on the numbers of different types of animals who are killed and considers a definition of the term “humane”. It contains a detailed evaluation of the different methods of killing currently used, including hunting, chemical control methods and the release of species-specific diseases. After evaluating the more humane alternative methods, the author ends with a plea for more resources and research into understanding and developing methods of population control which reduce wild animal suffering.

Turning to invertebrates, the discussion around controlling their populations is complicated by many people’s unclear understanding of whether these animals can suffer at all. We need to act on incomplete understandings, however, and if they can indeed suffer, it seems likely that most invertebrates have lives which are overall negative, rather than positive. Therefore, the paper surmises, ending their lives painlessly, or preventing their reproduction, could actually be positive interventions.

After consideration of this issue, there is analysis of the physiological effects of pesticides, suggesting that insecticides which affect multiple types of insect are possibly more humane than insecticides which only affect “target species” of insects. This is because they may reduce unnecessary suffering and the total number of deaths. Some insecticides cause suffering over dragged out periods of time, while others are faster acting, and these are probably more humane, although they might cause more intense suffering over short periods of time. The effectiveness of biological methods of population control, such as the use of predators, parasites, and disease, is unclear.

Finally, the paper gives impressions on the costs of the different methods, noting that artificial population reduction is, in general, “lengthy, costly and less effective”. This leads the author to conclude that more research is needed, but that fast-acting insecticides which affect all insects (rather than focusing on a target species), combined with behaviour modification, could be the best approach in the meantime.

Unfortunately, however, there is no data in either the paper on invertebrates or on vertebrates on the costs of different intervention types. Apart from the author’s brief comments on the costs of invertebrate behaviour modification, it makes it hard for advocates to know how easy it would be to encourage companies or governments to consider these different methods.

Nevertheless, these papers are likely extremely useful for interested farmers and regulators, as well as for advocates to understand the current state of our knowledge. Clearly more research is needed, but these two papers will help to drive progress in the area.