1. Introduction

In the summer of 2019, the Florida Fish and Wildlife Conservation Commission (FWC) updated its webpage on the “invasive green iguana”. Green iguanas are native to Central America, but starting in the 1960s, people began to notice them roaming wild. Although the timeline is unclear, it seems that they were brought into the US as pets. Some were released into the wild by their owners; others probably escaped. Since then, they have flourished in Florida with especially large populations in the southern part of the state. Richard Engeman, a biologist for the National Wildlife Research Center, said in 2018:

“There’s no real way to come up with a valid estimate of the number of green iguanas in Florida. But the number would be gigantic. You could put any number of zeros behind a number, and I would believe it”. 1]

This has led to predictable conflicts. According to the FWC:

“Green iguanas cause damage to residential and commercial landscape vegetation and are often considered a nuisance by property owners… Some green iguanas cause damage to infrastructure by digging burrows that erode and collapse sidewalks, foundations, seawalls, berms and canal banks. Green iguanas may also leave droppings on docks, moored boats, seawalls, porches, decks, pool platforms, and inside swimming pools. Although primarily herbivores, researchers found the remains of tree snails in the stomachs of green iguanas in Bill Baggs Cape Florida State Park, suggesting that iguanas could present a threat to native and endangered species of tree snails. In Bahia Honda State Park, green iguanas have consumed nickerbean, which is a host plant of the endangered Miami Blue butterfly. As is the case with other reptiles, green iguanas can also transmit the infectious bacterium Salmonella to humans through contact with water or surfaces contaminated by their feces”. 2]

Additionally, green iguanas appear to be responsible for power, phone, and Internet outages, as they both chew through cables and stretch themselves across power lines [ 1 ]. There is also some evidence that, on occasion, they use the burrows of other threatened species, such as the Florida burrowing owl [ 3 ].

Based on these concerns, the FWC urged homeowners to “kill green iguanas on their own property whenever possible” [ 2 ]. A few weeks later, however, they had to qualify that comment. In a press release, FWC Commissioner Rodney Barreto said:

“Unfortunately, the message has been conveyed that we are asking the public to just go out there and shoot them up. This is not what we are about; this is not the ‘wild west’. If you are not capable of safely removing iguanas from your property, please seek assistance from professionals who do this for a living”. 4]

The FWC press release was partially motivated by a surprising amount of national coverage, which only increased after a man was hunting iguanas with a pellet gun and accidentally shot the person who was maintaining his pool [ 5 ]. However, the FWC has not changed its basic position. In the FAQ portion of its site on the green iguana, it now says this:

“Green iguanas are not protected in Florida except by anti-cruelty laws and can be humanely killed on private property year-round with landowner permission. The FWC encourages removal of green iguanas from private properties by landowners. Members of the public may also remove and kill iguanas from 22 FWC-managed public lands without a license or permit under Executive Order 17-11. Captured iguanas cannot be relocated and released at other locations in Florida. Homeowners that trap iguanas on their property may be able to obtain euthanasia services from local exotic veterinarians, humane societies or animal control offices depending on the location and availability of services”. 2]

Florida may not be the “wild west”, but for the green iguanas, there is not much difference between the revised statement and the original one.

7,8,9, We do not tell this story because it is unique. To the contrary, this kind of invasive species “management” is entirely ordinary, as there have been many cases in which Fish and Wildlife commissions have tried to enlist the public to “manage” invasive species. In Texas, for instance, the state recently removed the requirement that people have a hunting license before killing feral hogs, Louisiana has long offered a bounty on nutria to encourage hunters to pursue them, Illinois offers grants to Asian carp processors to encourage them to create consumer demand for these fish, Georgia has asked its anglers to kill northern snakeheads, and Pennsylvania recently told the public to kill spotted lanternflies [ 6 10 ]. Instead, we tell this story because we want to explore a side of it that has not received sufficient attention in animal rights theory—namely, the extent of wrongful discrimination.

moral patients , i.e., beings who are deserving of direct moral consideration. We acknowledge that not all animals are moral patients, as some may not even be sentient (such as bivalves). Plainly, there is debate about the ground of moral status. Perhaps the most prominent options are associated with utilitarianism and the rights view. Peter Singer [16, Animal rights theory claims that at least some animals are, i.e., beings who are deserving of direct moral consideration. We acknowledge that not all animals are moral patients, as some may not even be sentient (such as bivalves). Plainly, there is debate about the ground of moral status. Perhaps the most prominent options are associated with utilitarianism and the rights view. Peter Singer [ 11 ], for instance, argues that sentience is both necessary and sufficient for being a moral patient. By contrast, Tom Regan [ 12 ] argues that being an experiencing-subject-of-a-life is sufficient for having moral rights. We assume that, given their neurological and behavioral complexity, green iguanas are both sentient and subjects-of-a-life. Studies indicate that reptiles, including iguanas, experience pain [ 13 14 ], attempt to maximize sensory pleasure [ 15 16 ], experience basic emotional states [ 15 17 ], and engage in the kind of social behavior that people once assumed to be unique to mammals [ 18 ]. For instance, green iguanas have emotional responses to stressful handling experiences, which indicates “emotional fever” [ 19 ]. Although few researchers have explored reptile intelligence, the studies that have been conducted indicate that reptiles have some sophisticated cognitive capacities, including the ability to solve complex problems and apply what they have learned in the future [ 20 21 ]. Given our limited knowledge of reptile mental life and the evidence that points to reptile cognitive complexity, we ought to adopt a policy that errs on the side of caution by giving green iguanas the benefit of the doubt and treating them as if they are moral patients, as Regan [ 12 ] (p. 320) suggests for the case of late-term fetuses.

speciesism , often defined as the “prejudice or attitude of bias in favor of the interests of members of one’s own species and against those of members of other species” [ human species. Regan [ Given as much, the standard story from animal rights theory is that animals are victims of, often defined as the “prejudice or attitude of bias in favor of the interests of members of one’s own species and against those of members of other species” [ 11 ] (p. 6). Regan [ 12 ] (p. 155) claims that the paradigm case of speciesism is when animals are denied membership in the moral community because they do not belong to thespecies. Regan [ 22 ] (p. 47), like Singer, emphasizes that it is speciesist to ignore the interests of animals or count them as less than the interests of human beings “simply because animals do not belong to the ‘right’ species”.

Obviously enough, any anti-speciesist is going to have serious objections to the killings that we have described. Granted, it is not costless to have green iguanas around. However, that hardly shows that the FWC has given adequate reasons for aggressive lethal management. On the one hand, we have the most significant harms that sentient beings can suffer: acute pain and death. On the other, we have weak evidence that the green iguanas have negative impacts on native species and strong evidence that they are inconvenient for human beings, raising concerns about sidewalk integrity, aesthetics, disease transmission, and the like. Moreover, even if the iguanas cause serious harm to the environment, it does not follow that they are causing serious harm to the rights-bearing parts of the environment—those individuals who are experiencing subjects-of-a-life. So, if people insist that the iguanas be killed, they seem to be guilty of speciesism. We might surmise, then, that there is little left for animal rights theory to say about this situation. The interests of green iguanas are being discounted relative to the interests of human beings “simply because they don’t belong to the ‘right’ species”, and, as a result, they are being unjustly killed.

But on our view, neither Singer’s nor Regan’s anti-speciesist theories explain the full extent of the discrimination at play. We suspect that what is particularly objectionable about the way green iguanas are being understood and targeted is that they are being wrongfully discriminated against, even relative to other non-human animals. To see whether this intuition can be defended, we extend Deborah Hellman’s [ 23 ] discrimination ethic to argue that the classification of green iguanas as “invasive” constitutes a kind of wrongful discrimination that is not explained by traditional accounts of speciesism. Moreover, we argue that its being wrong to categorize the green iguanas as invasive is perfectly compatible with its being morally permissible to kill them—assuming that conservationists “kill equally”. It simply is not compatible with the standard that conservationists tend to employ in their decisions about who lives and who dies.