I now move on to the most pressing challenge to companion veganism. It might be said that while we do have an obligation to abstain from inflicting suffering upon and killing sensitive NHAs, this obligation is overridden by the fact that our companions require the flesh of NHAs to be healthy. There is received wisdom in the area (Donaldson and Kymlicka 2013, 143; Rothgerber 2014) that while dogs can thrive on vegan diets, cats may not be able to. Indeed, it is not hard to find authoritative-sounding statements endorsing this claim. For example, on the popular website WebMD, Roxanne Hawn quotes Cailin Heinze (a veterinary nutritionist) as saying that, “[f]or cats”, a vegan diet is “ really inappropriate. It goes against their physiology and isn’t something I would recommend at all. For dogs ... vegan diets can be done, but they need to be done very, very carefully” (Hawn 2011). Hawn also quotes the guardian of cats fed a vegan diet, who explains that her cats are happy and healthy (2011). It is not hard to find anecdotal evidence of vegan cats thriving on the one hand and angry condemnation of guardians of vegan cats on the other.
Here is not the place to solve this particular dispute, especially as the scientific literature seems equivocal. In a review of the evidence, Kathryn Michel concluded that the nutritional adequacy of some commercially available vegan cat foods has been “called into question,” but did not claim that vegan diets are necessarily unsuitable (2006, 1275-77). By contrast, a study (Wakefield, Shofer, and Michel 2006) examining individual cats found that vegetarian diets (including vegan diets) did not have the adverse health effects expected. Lorelei Wakefield, the veterinarian who was the lead author of the latter study, runs VegetarianCats.com, a website with information about vegetarian and vegan diets for companions. She is of the view that a plant-based diet for cats is possible, having raised vegan cats, but can be difficult, especially if the cats have pre-existing health problems.
Given the conflicting comments from experts, this fourth challenge seems a serious one for my argument. Were cats unable to survive on a vegan diet, and assuming that they could not be provided flesh in a respectful way, it could be that we would have to explore whether there was some way we could balance our positive duties toward cats with our negative duties toward other NHAs. One solution, unthinkable to some, would be companion cats’ extinction. Though we may have good reasons to think cats’ extinction would be a bad thing, we also have very good reasons to be opposed to continuing to feed flesh to cats. Another possible solution, though one perhaps equally problematic, is genetically modifying cats away from carnivory. The way forward seems unclear.
But let us take a step back. The issue of companion diet is more complicated than I have previously allowed. First, our obligations concerning dogs and cats may be different, given their different physiologies.6 Second, our obligations concerning companion diet have both moral and political dimensions. The moral dimension focuses on the actions of guardians, while the political dimension focuses on the actions of the state and society—for example, decisions about research funding. In the case of dogs, the moral and the political dimensions are close: we should want to see dogs converted to veganism. For individual animal lovers, this means careful research and a change in companion diet. For states, the obligation will, in the medium-term, mean the banning of flesh-based “pet food.” More immediately, it might mean information campaigns and subsidies on vegan dog foods, both of which could be funded by a tax on flesh-based dog foods.
With cats, individuals and states appear to have somewhat different obligations. Individual animal lovers should not want to risk their companions’ health. For guardians who are confident that they can provide a suitable vegan diet for their cats, this is the right choice, but such individuals may be in a minority. The solution for others is minimizing the amount of animal protein fed to companions. Preferable to a wholly flesh-based diet would be feeding cats “half vegetarian biscuits and half organic wet meaty food” (Brown and Welch 2010). A mixed diet could be combined with the seeking out of the most ethically viable NHA- derived products for companions: organic, free-range, “happy” meat still involves the infliction of an early, gruesome death, but at least there is typically less suffering. Perhaps there are better possibilities: the eggs of rescued chickens might be viable, but such chickens would not exist in a world in which chickens were not kept for their eggs. Though perhaps unpleasant, “road kill” provides a source of flesh that would be wasted otherwise. “Dumpster-diving” provides another alternative; again, though, dumpster-diving (which is criminalized in some jurisdictions) is a possibility only so long as we live in a society where NHA-derived products remain a “normal” part of the human diet, and so will hopefully become less viable in time.
Political solutions would involve seeking out a just alternative to current cat diets, perhaps through research funding. Most obviously, veterinarians can learn more about cat physiology and diets and so come to understand how they might easily thrive on vegan diets. For example, taurine is a nutrient that cats typically acquire from animal flesh, but vegan taurine supplements are already available— further development in this area is easily conceivable. Animal welfare scientists might be able to discover that certain NHAs are actually unthinking, unfeeling entities, in which case they would not be covered by the typical approaches to animal ethics. If these NHAs could be used to feed our cats, then it seems that the dilemma could be averted.
Research from animal ethicists and other normative theorists, too, could suggest creative solutions to the problem—both temporary and permanent. For example, in a world in which humans and dogs were vegan, there would be much space on which we could develop the most humane possible forms of farming.7 I defend an alternative elsewhere (Milburn 2015), suggesting that while the discovery of some nonsentient NHA that is suitable as a food source for cats would be ideal, in the meantime, we could be permitted to feed to cats those NHAs for whom sentience is plausible, but not likely, such as certain shellfish. Importantly, I argue that we may have different obligations concerning our cats’ diets than our own; while we could feed certain shellfish to our cats, we would not be permitted to eat them ourselves. (Individual animal lovers, if they are confident that shellfish could provide a suitable food source for their companions but are not confident that a wholly vegan diet could, could follow this route.) The question of companion diets is not solely a scientific one, but something to which normative theorists could offer much.