January 31, 2023

The possibility that some animals’ lives in the wild might contain more suffering than wellbeing gives rise to many of the research questions unique to the study of wild animal welfare. Here, we define the concept of net-negative lives and describe its implications for both basic and applied questions in welfare biology research.

Definition
A negative experience is an experience that an individual would rather not have had. A net-negative life is a life which an individual would rather not have lived, because their negative experiences outweighed their positive experiences. Net-negative lives can also be called “lives not worth living” (e.g., Wilkinson 2011).

Common applications
The concept of net-negative lives already guides some of the decisions people make for themselves and for animals. 

In places that allow voluntary euthanasia, a person with a painful terminal illness might choose to die because they expect the remainder of their life to be net-negative. 

When a person is caring for a pet dog suffering from a painful terminal illness, they can’t ask the dog directly, so they do their best to understand what their pet is feeling and make the choice they think is in the best interests of their pet.

In addition to end-of-life decisions, the concept of net-negative lives can also inform decisions about when it is ethical to bring a life into existence. For example, it may be that chickens tend to have net-negative lives when they are raised in battery cages on industrial egg farms. Some people stick to plant-based diets in the hopes of reducing the number of animals bred and raised on such farms, because they believe it is wrong to bring an animal into a life that animal would rather not have lived.

Implications for wild animal welfare
There is concern that at least some groups of wild animals also have net-negative lives. This seems especially likely to be the case for populations where the majority of juveniles die (presumably painfully) shortly after being born. For example, Horta (2010) speculates that Atlantic cod (Gadus morhua) might have net-negative lives on average, because only about one in a million hatchlings survive to adulthood.

This possibility — that at least some animals would rather not have been born — is a crucial consideration in wildlife welfare management. Many efforts to help animals aim to increase their populations, but if the members of a population have net-negative lives on average, then such efforts are actually harmful to the animals.

Research needed
There is currently tremendous uncertainty around how to identify which wild animals live net-negative lives and how to address their needs. Welfare biology can reduce that uncertainty by advancing basic and applied science on three main fronts: sentience, life history, and wildlife management.

Questions about sentience focus on animals’ basic capacities to experience subjectively positive or negative mental states. Which animal species are sentient? At what life stage do animals of a given species develop sentience? How does sentience vary across species and life stages?

Questions about life history can be used to understand what kinds of lives animals are living. For a given population, how many individuals survive to each life stage? At each life stage, what are the major sources of positive or negative experiences, and how frequent are those experiences? How can we measure the impact those experiences have on animals’ well-being? Given these estimates, what is the relative balance of positive and negative experiences in the life of a typical member of the population?

Questions about wildlife management seek practical ways to apply these findings to benefit wild animals. If we can confidently identify which animals experience net-negative lives, are there effective interventions that could make their lives net-positive? If their lives are inevitably net-negative, should their populations be reduced so that fewer individuals suffer that fate? If so, what is the most humane way to do that? 

Of course, given the inherently subjective nature of welfare, research may never be able to completely eliminate uncertainty in the assessment of net-negative lives in the wild. Therefore, some of the most important management questions are about how to act under uncertainty. How can we quantify our level of uncertainty about the net quality of life in a given population? Are there interventions that would be robustly positive under a range of possible scenarios? Given our degree of uncertainty and the estimated severity of the animals’ needs, what is the expected value of a particular intervention?

Answering these questions will require progress in both the basic science and the applied science dimensions of welfare biology.

Further reading

• Browning and Veit (2021) propose a series of arguments for why animals might have net-positive lives, demonstrating the need for more empirical research on this complicated topic.

• Determining whether affected animals have net-positive or net-negative lives is one of the crucial considerations in evaluating the effectiveness of past interventions with the potential to improve wild animal welfare at scale. 

• Reducing populations from their carrying capacity to their optimal population density could be one way to improve wildlife welfare even when the net value of their experiences is uncertain.

• In some populations, contraception could reduce juvenile mortality without affecting the total population — preventing the lowest-quality lives while making it easier for others in the same population to thrive.

• Our list of research priorities shows how these questions relate to our broader research agenda.

References

Browning, H. & Veit, W. (2021). Positive wild animal welfare. Preprint. Check www.heatherbrowning.net for citation details once published. https://philsci-archive.pitt.edu/19608/1/browningveit2021positive_welfare.pdf

Horta, O. (2010). Debunking the idyllic view of natural processes: Population dynamics and suffering in the wild. T´elos 17 (1), 73–88. https://revistas.usc.gal/index.php/telos/article/view/284

Wilkinson, D.J. (2011). A life worth giving? The threshold for permissible withdrawal of life support from disabled newborn infants. American Journal of Bioethics 11 (2): 20–32. https://doi.org/10.1080/15265161.2010.540060