Ever since medieval times, cats have been used to control vermin overpopulation. Recent studies show that they might not be an ideal predator for the Norway rat, which is much too common on the streets of New York. A trash collection center camera filmed cats as they stalked rats. Interestingly though, they did not do much else than observe them. This tells us that cats are not the ideal way of pest control we thought they are.
Cats were unwilling to chase the rats, let alone kill them. The reason is that cats prefer smaller prey such as birds and mice. Another reason is that birds and mice do not fight back. Norway rats do, and they do so ferociously. The size difference between a Norway rat and Brooklyn mouse is almost tenfold. The average weight of a mouse is some 30 grams while a full sized rat can weigh over 300 grams. During the course of 79 days, the cameras showed only three rats had been killed.
These results were gathered during a completely unrelated study conducted by Michael Parsons, a behavioral ecologist of the Fordham University in New York and his team. They released five lab rats with microchips into the trash collecting facility. Soon they caught the attention of feral cats that started chasing the rats around the facility. The researchers realized this is an ideal opportunity to study feral animals, and dropped their initial study.
The cats and rats adapted new behavioral patterns during the 79 days. The cats observed the rats more frequently and even started exploring the entrances to the rat’s homes in order to find them. On the other hand, the rats became much more careful in venturing into open spaces and were generally much harder to spot. Researchers think that this is why people believe that cats are so apt in controlling rat populations when in reality the rats only became warier and harder to see.
Instances when cats indeed attacked the rats were very rare. The researchers collected some 300 clips and only 20 of them showed any actual footage of a cat actively stalking a rat. The three rats that the cats did kill were victims of unfavorable circumstances. In all three of those situations, they were pounced on while trying to hide after being spotted outside their hideouts. In one clip the cat and rat partook in an almost dance-like chase sequence where the cat stopped to observe the rat every time the rat stopped moving.
In order to make the cats chase the rats, people often resort to withholding food from them. This makes them more susceptible to taking risks while searching for food. But doing this is considered inhumane, and the starved state of the cat lowers their chances of a successful hunt.
The results shown in this study mimic the one performed earlier in Baltimore. The cats were similarly uninterested in rats. The number of rats the cats do kill is not nearly big enough to help control the rat population.
Feral life is tough. The cats are at a constant disadvantage and because of this they often switch their focus to smaller prey such as birds. Recent reports tell us that cats are responsible for more than a billion bird killings each year.