Evolutionary reasons why suffering prevails in nature

One of the main reasons the majority of nonhuman animals may experience more suffering than wellbeing in nature has to do with the fact that many more animals are born than can survive. This has not merely happened to be the case by chance. There are reasons for high mortality rates that are deeply rooted in the very way evolutionary processes occur.

Ecology and natural history are not shaped by the interests of living individuals; they are shaped by the transmission of genetic information. The relationships between different individuals, and between individuals and their surroundings, are due to the features those individuals have, the way they act, and the resources that are available in their surroundings. What determines the features and behavior of individuals is their genes combined with the way their environment has affected them and what they have learned from it. But what determines their genetic makeup in the first place? Why do different individuals carry certain information in their genes that leads them to be and behave in certain ways?

The simple answer is because that information has been transmitted to them. Their ancestors had certain genetic information that they passed on to new beings (with some mistakes occurring in the process every now and then, leading to mutations). If their ancestors had had different information, or if the genetic information their ancestors had was not transmitted, then there would be no beings now with that genetic information. There are certain beings in the world because certain genetic information was transmitted instead of other genetic information. This genetic information determines that they exist as the kind of beings they are, including, among other things, whether they are sentient (conscious).1

Not all genetic information is equally likely to be transmitted. The more certain genetic information “promotes” itself to be transmitted, the more likely it is to be transmitted.2 That is, if a certain set of genetic information makes the beings who have it fitter to transmit it, then there will be a greater chance that future beings will have that genetic information. If genetic information makes the beings who have it unable to transmit that information, then there will be no living beings who inherit it.

It is due to this that certain reproductive strategies have been selected for by evolution.3 The reproductive strategies that exist in nature are those that better promote the transmission of the genetic information of those individuals who follow them. This is why most animals have huge numbers of offspring. The text on why reproductive strategies maximize suffering explains that this causes immense amounts of suffering to occur in nature. Reproduction does not occur for the sake of the maximization of the happiness of individuals, but for the mere sake of the transmission of genetic information.

As explained in the text on the problem of consciousness,4 positive and negative experiences appeared in natural history because they favor the transmission of genetic information. Usually, when individuals act in certain ways that are favorable to the transmission of genetic information (as happens in some cases in which they do things that are good for their survival or when they reproduce) they have positive experiences, while when things happen to them that make them less fit to transmit their genetic information (as when they suffer harms that risk their survival) they have negative experiences.

Because of this, the happiness of individuals will increase when they have enough resources to satisfy their interests. However, when those resources are not sufficient, their happiness will substantially decrease. In fact, when those resources are not enough to meet their needs, they will suffer. The less they have, the more they will suffer.

This explains why suffering outweighs happiness in nature. The mechanisms that determine which individuals come into existence are such that far more individuals come into existence than can survive with the resources available.5 The resources can sustain only a tiny minority of the animals who come into existence. Due to this, most of them will suffer and die shortly after being born.

Many of these animals are conscious. One important way genetic information drives the behavior of individuals is through positive and negative experiences, which only conscious beings can have. And this mechanism implies that conscious animals suffer when they don’t have the resources they need. Plus, because of the way the transmission of genetic information occurs, if there were resources available for all at any particular moment in time, that would change almost immediately because individuals would then multiply as much as they could, until there were only resources available for a small percentage of them.

It is due to this that suffering outweighs happiness in nature. The deaths of most individuals who come to existence due to the prevalent reproductive strategy (consisting in bringing into existence large numbers of offspring) is the clearest way this happens. Other ways are due to hunger and thirst, parasitism, predation, and diseases (at least in the case of infectious disease).

Indirectly, many of the harms animals in nature suffer for other reasons, such as climate or injuries, may be ultimately due to their reproductive strategy, because they may suffer injuries when they are trying to meet their needs or suffer from weather conditions because population pressure pushed their ancestors or themselves to dwell in harsh environments.

We must also note that happiness and suffering are not perfectly adjusted to their original cause. In natural history, those features determined by genetic inheritance are selected simply when they work well enough to make a difference for genetic transmission. It is not necessary for them to work perfectly. So, conscious individuals have positive and negative experiences even if they themselves will never reproduce or contribute in other ways to the transmission of their genetic information (that is, helping other individuals with shared genes to reproduce). Because of the way population dynamics works, the balance between positive and negative experiences may be negative for the majority of conscious animals who are ever born.

Further readings

Catania, A. C. & Harnad, S. (eds.) (1988) The selection of behavior, Cambridge: Cambridge University Press.

Clarke, M. & Ng, Y.-K. (2006) “Population dynamics and animal welfare: Issues raised by the culling of kangaroos in Puckapunyal”, Social Choice and Welfare, 27, pp. 407-422.

Colgan, P. (1989) Animal motivation, London: Chapman and Hall.

Darwin, C. (1860) On the origin of species, New York: D. Appleton and Company [accessed on 17 January 2013].

Darwin, C. (2018 [1860]) “Letter no. 2814”, Darwin Correspondence Project Darwin [accessed on 29 August 2018].

Darwin, C. & Wallace, A. (1858) “On the tendency of species to form varieties; and on the perpetuation of varieties and species by natural means of selection”, Proceedings of Linnean Society, 3, pp. 45-62.

Dawkins, M. S. (1990) “From an animal’s point of view: motivation, fitness, and animal welfare”, Behavioral and Brain Sciences, 13, pp. 1-9.

Lack, D. (1954) The natural regulation of animal numbers, Oxford: Clarendon.

Reznick, D.; Bryant, M. J. & Bashey, F. (2002) “r-and K-selection revisited: The role of population regulation in life-history evolution”, Ecology, 83, pp. 1509-1520.

Richards, R. R. (1989) Darwin and the emergence of evolutionary theories of mind and behavior, Chicago: The University of Chicago Press.

Rolston, H., III (1992) “Disvalues in nature”, The Monist, 75, pp. 250-278.

Sagoff, M. (1984) “Animal liberation and environmental ethics: Bad marriage, quick divorce”, Osgoode Hall Law Journal, 22, pp. 297-307 [accessed on 15 April 2018].

Stearns, S. C. (1992) The evolution of life histories, Oxford: Oxford University Press.

Tomasik, B. (2014) “The predominance of wild-animal suffering over happiness: An open problem”, Essays on Reducing Suffering [accessed on 3 December 2014].


1 Dawkins, R. (2006 [1976]) The selfish gene, 30th Anniversary ed., New York: Oxford University Press; (1999 [1982]) The extended phenotype, Oxford: Oxford University Press. Smith, J. M. (1998 [1989]) Evolutionary genetics, 2nd ed., Oxford: Oxford University Press, p. 10. Mayr, E. (1997) “The objects of selection”, Proceedings of the National Academy of Sciences of the USA, 94, pp. 2091-2094 [accessed on 9 January 2013]; (2001) What evolution is, New York: Basic Books.

2 Fisher, R. A. (1930) The genetical theory of natural selection, Oxford: Oxford University Press; Hamilton, W. D. (1964) “The genetical evolution of social behaviour I”, Journal of Theoretical Biology, 7, pp. 1-16; Dawkins, R. (1982) “Replicators and vehicles”, in King’s College Sociobiology Group (eds.) Current problems in sociobiology, Cambridge: Cambridge University Press, pp. 45-64; Mayr, E. (1997) “The objects of selection”, Proceedings of the National Academy of Sciences of the USAop. cit.

3 See Pianka, E. R. (1970) “On r- and K- selection”, American Naturalist,104, pp. 592-597; Parry, G. D. (1981) “The Meanings of r- and K-selection”, Oecologia, 48, pp. 260-264; Roff, D. A. (1992) Evolution of life histories: theory and analysis, Dordrecht: Springer. See also the bibliography in the Population dynamics and animal suffering.

4 This can be seen in Ng, Y.-K. (1995) “Towards welfare biology: Evolutionary economics of animal consciousness and suffering”, Biology and Philosophy, 10, pp. 255-285. Many more references are available in the section on animal sentience.

5 Suffering and death therefore occurs out of competition at both intraspecies and interspecies level. See for instance Cannon, G. B. (1966) “Intraspecies competition, viability, and longevity in experimental populations”, Evolution, 20, pp. 117-31; Connell, J. H. (1983) “On the prevalence and relative importance of interspecific competition: Evidence from field experiments”, The American Naturalist, 122, pp. 661-696; Chesson, P. L. (1985) “Coexistence of competitors in spatially and temporally varying environments: a look at the combined effects of different sorts of variability”, Theoretical Population Biology, 28, pp. 263-287.



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