Several Weeks ago CASS at CFI Canada received an email from a resident of Stratford, Ontario who was asking for our help in researching and commenting on a new conservation plan that has been sweeping through the US and Canada. “Trap-Neuter-Return” or TNR has recently been adopted by the Ontario Society for the Prevention of Cruelty to Animals (OSPCA) to deal with feral cats and they are planning to promote it in municipalities around Ontario, including Stratford. Our Stratford resident was distressed at this prospect and called it pseudoscience.
I remember visiting Rome and coming across a local legend of a lady who was feeding the population of feral cats around the Coliseum with pasta and tuna – and the scrawniest, saddest looking cats were everywhere around the structure. In the Junction section of the west end of Toronto, there is a large feral cat population that runs alongside the rail corridor. Peter Marra, a wildlife professional and author of this article in the Washington Post estimates that there are any where from 80 to 120 million free-roaming cats in the US alone and that cats constitute the largest number of predators on the planet. The Toronto Humane Society estimates that between 20 000 and 100 000 cats live on the streets of Toronto. They have been introduced into most parts of the world, usually dumped by owners who are too lazy to find them a home, let alone get them neutered, or allowed to run free outside of their home and never to return. Trapping and euthanasia is the standard practice to deal with feral populations, but TNR is being adopted in many jurisdictions. TNR is supposed to have originated in Denmark and is now practiced in most US states at various levels, both by private individuals and by local SPCA’s.
TNR is a process of trapping cats from feral populations, testing and vaccinating for various diseases, based on the jurisdiction, neutering, and then returning them to the location where they were captured. It is offered as an alternative to euthanasia and it is the goal of various organizations like Alley Cat Allies and Stray Cat Alliance to achieve a “no-kill” state for humane societies and SPC’s all over the US. The scientific claims made by TNR proponents include:
- The permanent removal of cats for euthanasia creates a “vacuum effect” where cats from neighboring populations will move in and replace those cats removed. TNR replaces the cat population with neutered individuals who will defend their territory and not reproduce.
- It follows that the population will decline “naturally” through attrition and the natural death of the neutered felines
- Predation by the cats on local bird, mammal, lizard and insect populations can be kept in check by making sure the cats are fed and have shelter and cats can be a natural part of this urban ecosystem
Chris Hassell is a conservation ecologist, a CASS advisor, and a member of CFI Ottawa. Hassell reviewed the limited evidence for the practice of TNR and reported on his findings to our group in April. There is a good review of the evidence by Longcore et al that does a comprehensive job at addressing the claims made by proponents of the practice, and Hassell summarized the evidence as follows:
- Successful TNR studies tend to focus on animal welfare as a success, rather than the decline in populations of feral cats. This is not what conservation biologists or policy makers are looking for.
- High rates of neutering (beyond those that have ever actually been achieved) are necessary to cause a decline in populations. A number of long term studies on TNR have found that it isn’t worth the effort.
- Success attributed to TNR is partially due to the removal of animals through adoption.
- Some studies have involved the researchers’ participation, which increases the chances of success, compared to volunteer participation.
- Few studies have actually demonstrated the removal of a population by TNR, and then only after much effort.
- There is no evidence that the “vacuum effect does not follow the death of neutered cats.
- TNR focuses on maintaining colonies of feral cats on the basis that they are not harmful to the local environment. This is completely ridiculous. The article contains a number of citations of studies demonstrating
- extinctions caused by cats
- threats to wildlife in yards and gardens which provide much-needed habitats in otherwise inhospitable urban environments
- far higher densities (and therefore predation pressure) of feral cats than natural, native species resulting either from TNR colonies or feeding of domestic animals
- cats do not necessarily hunt because they are hungry so satiating them will not help
- cats play an important (negative) role in fluctuating bird populations (especially ground-foraging and rare species)
- cats cause tens of millions of bird, mammal and reptile deaths in the UK, and a similar number in Wisconsin
- feral cats carry diseases (for which they also act as reservoir hosts) which they transmit to local cat populations, local wildlife and humans (these diseases are not adequately treated in TNR schemes)
The science behind TNR does stand on shaky ground, but if we were to limit the debate to the science it seems like there would be small areas of equivocation. When run by professionals and paired with aggressive adoption, TNR may be viable. At the very least it deserves to wend its way through the process of scientific inquiry to see if it can be tweaked to work and, if not, abandoned for more successful measures. I am not convinced that it would, given the Longcore et al review, but the scientific debate itself does not seem pseudoscientific.
The Toronto Humane Society, on its page on TNR, which it supports, suggests that you check out a facts page from the American Veterinary Medical Association which lists 4 studies, only one of which concludes that TNR works, and only after 47% of cats from a 68 cat population had been removed for adoption and not returned. Another concludes that in order to work you must have neuter rates of 71-94%; a very ambitious number. The third article, from Anderson et al, concludes that euthanasia is a better approach to management. This is certainly equivocal science and if this is the information that the THS is expecting will convince us to adopt TNR, they are not looking at the facts and may be blinded by their ideology in this respect.
What is at the crux of the matter, however, is that those proponents of TNR are not conservation or wildlife professionals; they are members of the public or veterinarians that are approaching the management of feral populations using an ethical standard, not a scientific one. The Wildlife Society, Canadian section, has this to say about feral cat populations:
“Feral and free-ranging domestic cats are exotic species to North America. A growing body of literature strongly suggests that domestic cats are significant predators on native wildlife and serve as reservoirs for several diseases that can have significant effects on the health of humans, wildlife, and domestic animals. TWS supports the humane elimination of feral cat colonies, passage of local and state ordinances to prohibit the feeding of feral cats, and educational programs that inform the public on feral cats, the importance of keeping pet cats indoors, and encourage owners to neuter or spay their cats.”
Iain Martel, a philosopher of science and a co-chair of CASS pointed out the apparent gap in environmental ethics when it comes to dealing with feral populations:
“Animal welfare activists and conservation biologists simply have different views of what counts as success. At the extremes, one side only values the lives of cute cuddly critters, giving no value to vermin, whereas the other side only values the lives of native species, viewing anything else as an alien invader to be destroyed. On this level, science is helpless to adjudicate the dispute – only a fully worked-out environmental ethic can do so.”
This is an important point: if your purpose is to protect populations of cats, a species that has been bred by humans to be attractive, affectionate and companionable, (see Deirdre Barrett’s description of supernormal stimuli of our nurturing instincts) then TNR may indeed be the best way to manage this population in a way that does not result in the destruction of the cats by humans through euthanasia. The Toronto Humane Society’s goals seem centred around reducing the euthanasia rate of cats in Toronto, not controlling the number of feral cats on the streets. Conservation biologists are focused on the negative impacts that feral populations of domestic animals have on the ecosystem. It is disingenuous for groups like the OSPCA or THS to present their plans as a scientific alternative when they have not provided the evidence to support their assertions.
Pseudoscience as described by the Skeptics Dictionary is, among other things, a “set of ideas based on theories put forth as scientific when they are not scientific.” Once again, we have a solution starting from an ideology: “all cats deserve to live and we must act to protect them.” Proponents then cherry pick data that supports their ideology and ignore the data that does not. They then make unsupportable assertions like “TNR is the only strategy for controlling feral populations that has been proven to work” in order to generate support for the idea and with the hope that policy makers will not check the facts. As well, it is not clear that cats living feral live happy lives – they will eventually die, and not often of old age. The question of protecting their life at all costs when euthanizing them may be the actual ethical and humane thing to do, if they can’t be adopted out, deserves to be explored by ethicists without an ideological clamor.
If not pseudo-science it is certainly disingenuous of TNR supporters to call their idea supported by the science: currently, it is not. It is important when holding public debates on the issue to define what a success means: preventing the killing of feral cats or controlling populations to protect the ecology. TNR may certainly do the former, but it remains to be seen if it will do the latter, and the evidence is not looking good.
However, it is obvious that the best strategy would be to prevent the cats from entering the population in the first place, and it is best to quote Bob Barker on this one: “Remember to have your pet spayed or neutered!”
Pictures from Creative Commons, in order from top left to bottom: LTshears, Yanjig Lu, Lisa Wilson