Wildlife fertility control research

Can we improve the welfare of some species of wild animals by treating them with contraceptives?

This profile is tailored towards students studying biological sciences and psychology, however we expect there to be valuable open research questions that could be pursued by students in other disciplines.

Why is this a pressing problem?

There are an enormous number of wild animals in the world, vastly outnumbering humans and domesticated and farmed animals. Yet the welfare of wild animals is a highly neglected area of research when contrasted with research on the welfare of humans or domesticated animals. Some plausible hypotheses regarding the distribution of welfare among individuals of different species of wild animals have nonetheless been put forth. One is the argument from life history, which describes how fecundity and life-span might be related to welfare. This argument states that highly fecund animals will produce offspring in excess and most individuals will perish before reaching sexual maturity, sometimes due to a lack of available resources. Such exceedingly short life-spans will probably have lower average welfare than the lives of the few lucky individuals who survive until adulthood, although adult animals may also suffer from a lack of food, water, or shelter due to resource constraints.

If a lack of resources is indeed a common issue for wild animals, and if the argument from life history is broadly correct, we would expect fertility control to have positive effects on the average welfare of the target species through increased condition and survival of the remaining individuals, as long as possible side-effects of the treatment can be avoided. A lower population size would plausibly lead to reduced competition for resources, which ought to lead to higher average welfare, and possibly also higher total welfare. This is a bit more than just a theoretical argument though; humans have already escaped the Malthusian trap we were in, partly by artificially reducing our own fertility.

Although wildlife contraception research has been conducted for decades – for example, oral contraceptives have been used on pigeon and squirrel populations, and contraceptive darts to control deer populations – it has generally not focused on the welfare impacts of contraception. More research in this direction could help us find promising opportunities to improve wild animal welfare. Improving wild animal welfare is often seen as an intractable problem, so finding and thoroughly investigating promising small scale and near term solutions like contraception also seems like a very promising way to escape a vicious cycle of helplessness and disinterest.

See the video below on how wildlife fertility control can improve animal welfare.

    • Brennan, Ozy (2018) Wildlife Contraception

    • Elmore, Holly (2022) The Rodent Birth Control Landscape, Rethink Priorities

    • Rutberg, Allen T. (2013) Managing Wildlife with Contraception: Why is it Taking So Long?, Journal of Zoo and Wildlife Medicine

    • Turner, John W. & Allen T. Rutberg (2013) From the Pens to the Field: Real-World Wildlife Contraception, Journal of Zoo and Wildlife Medicine

    • The Botstiber Institute maintains this archive of research related to wildlife fertility control.

    • The Wild Animal Initiative, an organisation helping to build the field of wild animal welfare research.

    • The Botstiber Institute, an organisation using fertility control methods to mitigate human-wildlife conflicts.

    • Sign up for the Wild Animal Initiative newsletter and Animal Ethics newsletter to stay up-to-date with news in this area.

Contributors: This profile was last significantly updated in April 2022 based on this report from the Wild Animal Initiative. The thanks for first writing this profile to Simon Eckerström Liedholm. Learn more about how we create our profiles.

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