March 8, 2023

At Wild Animal Initiative, we use “welfare” to mean the aggregate quality of subjective mental experiences, at a given point in time or over a given period of time, for an individual or a group of individuals.

“Subjective experiences” are good or bad feelings. We use “sentience” to mean the capacity to have such mental states. Note that this use of “sentience” doesn’t require the ability to reflect on or report those experiences; a sentient individual could have positive and negative feelings without being able to communicate to themselves or to someone else, “I feel this way.”

Other definitions of welfare

This definition reflects the way “welfare” is commonly used in scientific discourse (Mellor et al. 2020, Mellor 2017,Beausoleil 2018, Mellor & Beausoleil 2015, Fraser et al. 1997, Duncan 1993). However, it differs from some definitions of welfare in that it only describes mental states. Others also consider physical health (Sharp & Saunders 2011) or the expression of natural behaviors (Rollin 1993) to be components of welfare. We agree that health and natural behavior are major factors that affect mental states, but because they don’t wholly determine mental states, we prefer to clearly differentiate the outcome from the inputs. This is consistent with the approach used by the Five Domains model of animal welfare assessment:

“The first four domains [nutrition, environment, health, and behavior] focus attention on factors that give rise to specific negative or positive subjective experiences (affects), which contribute to the animal’s mental state, as evaluated in Domain 5 [the mental domain]” (Mellor et al. 2020).

Research needed

While the meaning of welfare is relatively simple in theory, there are many open questions about how it works in practice.

That starts with questions about who has welfare. Which species are sentient? At what point in those animals’ development does sentience emerge? How does the quality or intensity of sentience differ across species and life stages? 

The next set of questions deals with how to measure welfare. Given that we can’t measure subjective experiences directly (Nagel 1974, Muehlhauser 2017), what physiological or behavioral metrics can serve as proxies for welfare? What are the relevant baselines, ranges, and benchmarks we can use to interpret that data within and across species? How can we collect that data in the field: remotely, at scale, and in uncontrolled conditions? 

Finally, responsible wildlife welfare management will require understanding how to compare and combine different experiences. At the individual level, how do acute feelings compare to chronic feelings, or positive ones to negative ones? How can we estimate welfare at the population level, especially when quality of life varies greatly across individual members of the population? Similarly, how can we compare welfare across species in order to estimate total welfare at the community level?

Research on questions like these can advance the field of welfare biology and ultimately inform responsible welfare-driven wildlife management.

Further reading

• Our previous blog post “Definition of welfare” goes into more detail on the various uses of “welfare” in the literature and the considerations behind the definition we use.

• Mellor et al, (2020) describe the Five Domains model of welfare (first introduced in 1994) and recent updates to it.

• The Welfare Footprint Project has proposed a framework for estimating the relative welfare impacts of different negative experiences. Their method focuses on quantifying the duration of time an animal is in each level of estimated pain intensity.

References

Beausoleil, N., Mellor, D., Baker, L., Baker, S., Bellio, M., Clarke,, A., Dale, A., Garlick, S., Jones, B., Harvey, A., Pitcher, B., Sherwen, S., Stockin, K., and Zito, S. (2018). “Feelings and fitness” not “feelings or fitness” — the raison d’être of conservation welfare, which aligns conservation and animal welfare objectives. Frontiers in Veterinary Science (5): 296. https://doi.org/10.3389/fvets.2018.00296

Duncan, I. (2005). Science-based assessment of animal welfare: farm animals. Revue Scientifique et Technique 24 (2): 483-492. PMID: 16358502.

Fraser, D., Weary, D., Pajor, E., and Milligan, B. (1997). A scientific conception of animal welfare that reflects ethical concerns. Animal Welfare 6: 187-205.

Mellor, D. (2017). Operational details of the Five Domains model and its key applications to the assessment and management of animal welfare. Animals 7 (8): 60. https://doi.org/10.3390/ani7080060

Mellor, D., and Beausoleil, N. (2015). Extending the ‘Five Domains’ model for animal welfare assessment to incorporate positive welfare states. Animal Welfare 24: 241-253. doi 10.7120/09627286.24.3.241

Mellor, D., Beausoleil, N., Littlewood, K., McLean, A., McGreevy, P., Jones, B., and Wilkins, C. (2020). The 2020 Five Domains model: Including human-animal interactions in assessments of animal welfare. Animals 10 (10): 1870. https://doi.org/10.3390/ani10101870

Muehlhauser, L. 2017 report on consciousness and moral patienthood. www. OpenPhilanthropy.org. (Updated January 2018). https://www.openphilanthropy.org/2017-report-consciousness-and-moral-patienthood

Nagel, T. (1974). What is it like to be a bat? The Philosophical Review, 83, 435-450. Cornell University Press. http://www.esalq.usp.br/lepse/imgs/conteudo_thumb/What-Is-It-Like-to-Be-a-Bat-1.pdf

Rollin, B. E. (1993). Animal welfare, science, and value. Journal of Agricultural and Environmental Ethics, 6 (2), 44-50. 

Sharp, T., and Saunders, G. (2011). A model for assessing the relative humaneness of pest animal control methods. Australian Government Department of Agriculture.