All over the Internet, at the moment, there is the result of a study on the predation of rats by feral cats which took place in New York City, USA.
The conclusion of the study is that feral cats have little interest in attacking and killing rats. Therefore, the public has a misconception about the rat catching ability of the modern feral cat. There’s the age-old idea that cats are good at keeping down rat populations and indeed, the authors of the study, say that cats are commonly used as rat catchers. I disagree with that right away. I do not believe that cats are used that much, hardly at all in fact, to manage rat populations. However, nonetheless, some businesses and shopkeepers do use cats for that purpose.
The first point to make is that the study concludes that cats do not ‘influence large urban rats’. By large they mean rats over 300 grams in weight. They openly admit that cats are more likely to prey on smaller animals below 250 g. The size of the rats may be a critical influencing factor.
My research indicates that the average weight of the brown rat is 230 grams. The black rat weighs between 110-340 grams. The brown rat is one of the most common rats, I understand, in the USA. The rats in the study were non-typical and larger than average at typically greater than 330 grams. This may have influenced the results.
Just five cats studied?
Secondly, the study videoed five feral cats distinguishable by their coat types. We know that cats vary substantially in their interest in hunting. It may well be the case that the five cats observed were less interested than average in hunting. This characteristic may have been exacerbated by the fact that they were fed quite well in the location where they were currently living.
Cats will obviously find the easiest source of food. If they are adequately fed and that food source is consistent and readily available then there is little incentive to prey upon large rats. There is also the possibility that the cats were semi-feral and less interested in hunting as a consequence.
Thirdly, and the study does touch on this as well, more work needs to be done on how feral and domestic cats deter rats. If, for example, a shopkeeper wants to deter rats from entering a facility, a domestic cat would in, my opinion, achieve that objective. The cat would not necessarily attack and kill the rats but he or she would be likely to prevent them entering the confines of the establishment.
The idea of deterrence is probably more valuable than actual killing. The presence of the cats may also affect how the rats breed and how they behave which may also have a detrimental effect upon their population size. These are other issues that need to be explored.
In conclusion, my preliminary thoughts about the study are that it is quite limited in its conclusions. I think we know that domestic and feral cats are not as good as people think at catching rats but neither are they as bad as the study suggests.
Dr Desmond Morris
Years ago, Dr Desmond Morris, in his famous book Catwatching asked the question “How efficient is the cat as a pest-killer?”. He mentions that the ‘contract’ between human and cat at the inception of the domestication of the wild cat was based upon the cat’s ability to kill rodents and other pests. So at the very beginning of cat domestication they must’ve been regarded as efficient pest-killers.
The cat’s urge to hunt is independent of the urge to eat. However, a cat will seek out the easiest sources of food so even though cats will hunt when not hungry they will choose prey which is the easiest to kill. Large rats are not necessarily easy to kill and could injure a cat.
He mentions a female tabby cat who lived at White City Stadium in London. Over a period of six years she caught no fewer than 12,480 rats which adds up to a daily average of 5 to 6. The general tenor of his section on this subject is that domestic and feral cats are regarded as efficient pest-killers.