Common methods of rat control often fail to consider animal welfare impacts
A study led by the University of Oxford has found that glue traps and anticoagulant poisoning are amongst the worst methods of rodent management when it comes to their impact on rat welfare.
Dr Sandra Baker, a Research Fellow at the University of Oxford, alongside a group of experts in wildlife management, rodent management, rodent biology, animal welfare science, and veterinary science and medicine, assessed the relative welfare impacts of six different methods of rodent control. Sandra is a member of the WAWC and three other members – Dr Pete Goddard, Dr Liz Mullineaux and Alick Simmons – are co-authors of the open access paper, published on 27 January 2022.
Many millions of rats - and mice - are estimated to be killed globally as pests every year. Two commonly used methods are glue traps (which are designed to catch rodents in a layer of extremely strong glue) and baiting methods (including anticoagulant poisons which interfere with blood clotting, killing rats through haemorrhaging). Rats are sentient animals (capable of negative and positive experiences) and yet both glue traps and baiting methods can lead to extreme suffering.
Dr Pete Goddard, WAWC chair, said:
“This research represents a major milestone in the journey towards recognition of wild animal welfare. People may not always like rats – and indeed, they can create public health concerns and lead to damage, particularly to food supplies, that must not be ignored – but they are sentient creatures and we have an ethical duty not to cause unnecessary suffering to any animals, wild or domesticated. I am delighted that members of the WAWC have been able to contribute to this groundbreaking work.
“In particular, on behalf of WAWC , I congratulate Sandra on bringing a complex project to such a successful conclusion, providing an authoritative welfare-based comparative analysis of methods currently used to manage rats."
The paper notes:
“Rats are probably the most intensively managed wild mammal species in the UK. Given our findings, and the dependency of management on lethal methods, especially anticoagulants, rat management may represent the greatest anthropogenic impact on wild animal welfare.”
Using a welfare assessment model, published data and expert knowledge, the control methods were compared and evaluated, to produce a relative welfare impact score for each. Methods included: lethal snap trapping; glue trapping, followed by concussive killing (a concussive blow to the head); live (cage) trapping, followed by concussive killing; two types of rodenticide poisoning (anticoagulant and cholecalciferol); and non-toxic cellulose baiting (which disrupts digestive systems, resulting in lethal dehydration).
The main outcomes of the study showed:
Glue trapping and the three baiting methods (anticoagulant poisoning, cholecalciferol poisoning and non-toxic cellulose baiting) all produced high welfare impacts and should be considered as last resorts from a welfare perspective.
In comparison, cage trapping, followed by concussive killing, scored lower welfare impacts.
The impact of snap trapping was highly variable, depending on the traps used, but high-quality snap traps could help produce the lowest impact, and therefore, the best welfare outcome, if used appropriately.
Where possible, any suffering should be minimised in rat control, however, until now, very little information has been available on the relative animal welfare impacts of methods currently being used in the UK. This has made it difficult to select the methods which cause the least impact on rat welfare. It is hoped these findings will help pest management professionals and the general public better understand and consider the welfare of these animals when selecting control methods.
Dr Sandra Baker, lead author of the paper, said:
“Rat management may represent the greatest source of anthropogenic impact on wild animal welfare. Our findings will help professional pest controllers and members of the public to reduce this impact by better incorporating consideration of animal welfare alongside other factors when choosing a rat control method”.
Dr Huw Golledge, chief executive and scientific director of Universities Federation for Animal Welfare (UFAW), said:
“This work is an important step in understanding the animal welfare impacts of various rat control methods. Its strength lies in the level of agreement reached by the diverse range of experts involved. At UFAW, members of the public often ask us for advice about the most humane way to control rat infestations. These results give us the information we need to provide advice on which methods are likely to have the least damaging effects on rat welfare. On the back of this research, we have comprehensively updated our webpage resource, which offers advice to the public on how to deal with rodent problems in the most humane way.”
Julian Kupfer, Chair of Trustees for the Animal Welfare Foundation (AWF), said:
“Given the current parliamentary discussions on rodent control measures we feel that this is a really important and timely scientific contribution. Rats have an enormous and varied impact upon our society. The resultant damage, combined with cost of their control, is a heavy financial burden for those sectors involved. However, rats are sentient beings and the welfare consequences of the various commonly used control methods have always presented a truly uncomfortable ethical dilemma.
“This authoritative paper provides a much needed objective look at the welfare impacts on rats of those control methods by experts from various disciplines and various countries. The results present a real advance in the understanding of those welfare impacts which will help shape present and future approaches, attitudes and research into rodent control. This should lead to effective management measures that at the same time pay due regard to animal welfare.”
The research was funded by UFAW (the Universities Federation for Animal Welfare), the Animal Welfare Foundation, and the Elinor Patterson Baker Foundation. It comes at an important moment as the proposed Glue Traps (Offences) Bill may restrict the use of these devices in England if it passes into law. The Scottish Government announced on 20 January that it intended to ban the sale and use of glue traps during the current parliamentary session, and the Welsh Government is consulting on similar measures.
The study was also supported by UKRI ERA-NET RodentGate project, the UKRI MRC GCRF rodent zoonosis control project and the African Union EcoRodMan project.
S.E. Baker, M. Ayers, N.J. Beausoleil, S.R. Belmain, M. Berdoy, A.P. Buckle, C. Cagienard, D. Cowan, J. Fearn-Daglish, P. Goddard, H.D.R. Golledge, E. Mullineaux, T. Sharp, A. Simmons, and E. Schmolz. 2022. An assessment of animal welfare impacts in wild Norway rat (Rattus norvegicus) management, Animal Welfare, 31: 51-68.
The full paper is available from Animal Welfare and can be accessed here: https://www.ingentaconnect.com/contentone/ufaw/aw/2022/00000031/00000001/art00005
DOI: 10.7120/09627286.31.1.005