A review of contraception methods for wild mammals

23 Nov 2023

Animal Ethics recently published a paper titled “Contraception in wild animals: A review of its use in mammals. It reviews the latest research on immunocontraceptive methods to help reduce human-animal conflict with wild mammal populations that have grown beyond their habitat’s capacity. As communities oppose lethal control methods like hunting or poisoning, they increasingly support contraception as a more ethical approach.

The paper was written by Jara Gutiérrez and Francisco Javier de Miguel of the Autonomous University of Madrid. It comprehensively surveys the current science on two major forms of immunocontraception for mammals – PZP vaccines and GnRH vaccines. It details how these vaccines work to temporarily sterilize animals, along with different methods to deliver them remotely or orally via bait. Researchers find that GnRH vaccines tend to be more effective than PZP, causing infertility for 1-2 years or more after just one or two doses.

The authors also closely examined the impacts of the contraception methods on animal health and behavior. Reactions at injection sites can sometimes occur, but physiological effects are generally mild. There is limited evidence overall on whether contraception fundamentally alters social dynamics or welfare. Additional studies monitoring wild animal contraception programs will further strengthen our understanding in these areas.

While hunting advocates oppose contraception, the paper notes growing public support for non-lethal management strategies. As contraception technology improves and becomes more affordable, it will likely expand to more species and contexts. The paper concludes that contraception can be part of comprehensive plans to improve the lives of wild animals.

This open access paper is a valuable resource both for scientists studying wild animal fertility control and communities debating the future of habitat management.

You can read the full text of the paper here:

Contraception in wild animals: A review of its use in mammals

You can read the abstract below:

Properly planned use of contraceptive methods in wild populations of various mammalian species can be successfully used to prevent lethal methods from being implemented, especially in urban and suburban areas. This study aims to review the most significant literature to date in relation to contraceptives. We have reviewed the modalities of application of immunocontraceptive vaccines, the evidence about the effectiveness of immunocontraception, the physiological, reproductive, ethological and social effects on the animals involved; and what the public’s reaction to immunocontraception will be. The available evidence indicates that significant detrimental side-effects are unlikely, both for the animals targeted by these programs and for other animals and humans, although more studies would be useful to confirm this.