Hi Emrik, 

Thanks so much for reading the article. I'm glad you found it interesting! I'm also concerned about the costliness of more humane alternatives, but perhaps there is some hope that some of the costs could be driven down if there was enough adoption to scale production. Some of the interventions may also be more costly in the short-term but prove less expensive than ARs in the long-term. In this case I have in mind things like rodent-proofing and deterrence. 

I agree with you too that from an advocacy perspective, alternatives to ARs are more likely to gain public support by appealing to the welfare costs of ARs to non-target beings like pets, children, and wild animals that aren't considered pests. 

I don't have a definite answer about domestic cats, unfortunately. As a cat companion, I am often disturbed by the  way they slowly hunt and kill their prey, but this may still be better than dying from ARs. On a more serious note, from what I've read and heard, one of the complications regarding domestic cats is their impact on non-target wildlife. Some of these costs could be mitigated using bell-collars and keeping cats indoors, although especially in informal settlements this would not be easy to regulate.

Hi Charles, 

Thanks for taking the time to read our article. You raise some good questions.

1. Concrete data on urban rat populations is very scarce, partly due to the difficulty and labour intensiveness of gathering data. Even when these studies are conducted, the numbers tend to be broad estimates based on nuisance reports or capture-recapture methods. For example, in 2014 the estimated rat population of New York City was around 2 million . Considering that Cape Town has a smaller population and lower population density than NYC, it is plausible that it has a smaller rat population. However, based on the frequent news coverage of rat infestations, especially in informal settlements, and the number of bait stations maintained by the city (over 10, 000 in 2020) it is likely that the population is significant. 
2. This is a great question, but again one that is difficult to answer, for the reasons outlined above, when it comes to populous small vertebrates (especially if they are considered pests or alien species and therefore not an ecological priority). The population s of more charismatic urban wildlife species are better studied. For e.g. there are an estimated caracals 45,000 to 150,000 across the entire country, and about 500 baboons in the Cape.  
3. Rats are numerous, their welfare is neglected, and the negative impact on their welfare due to the prevailing forms of population management are significant.
4. I don’t know the full answer to this one, but here is what I’ve come up with so far. I think many of the alternatives proposed here don’t compare very favourably from a cost-efficacy perspective to ARs. Alpha-chloralose, for example, is more expensive than ARs (Mason and Littin), and rodent-proofing can also be costly and time consuming. However, there is some evidence that snap traps can be favourably cost-effective compared to ARs (Mason and Littin). The Khayelitsha program (using live trapping) was also comparably low-cost to ARs . With regard to the development of more humane lethal methods, I am guessing that the research and development costs would be quiet significant.  
5. Our research so far suggests that some other cities in South Africa and in Africa use a similar rat management strategy to Cape Town, and in some instances have similar environmental and socio-economic drivers of their rat populations. In these instances the interventions and considerations explored in this research may be a valuable starting point.