Don't bother getting a factory cat

It seems that, contrary to popular opinion, cats are not good predators of rats.

In the US, researchers monitored the behaviour and movement of microchipped rats in the presence of feral cats living in the same area. They found that the rats actively avoided the cats, and only two rat kills were recorded in 79 days.

People have long associated cats as the natural enemy of rats. However, Australian and US researchers say cats prefer smaller, defenceless prey such as birds and smaller native wildlife — which makes cats a threat to urban ecosystems.

In the US study, researchers had been studying a colony of more than 100 rats living inside a New York City waste recycling centre when feral cats invaded the research area. The researchers then set up motion-capture video cameras to quantify the effect of the cats on the rats — the first time this has been studied in a natural setting.

The researchers examined 306 videos taken over 79 days. Although up to three cats were active beside the rat colony each day, only 20 stalking events, three kill attempts and two successful kills were recorded in this time. Both kills took place when cats found rats in hiding; the third attempt was an open-floor chase where the cat lost interest.

The videos also revealed that in the presence of cats, the rats spent less time in the open and more time moving to shelter and so were less visible.

This change in rat behaviour when cats are about could explain why people continue to release cats as ‘natural’ rat control tools. Seeing fewer rats the assumption is that the cats have killed them when in fact the rats are still there just less visible.

The study has been published as part of a special ‘rodent issue’ in Frontiers in Ecology and Evolution, with the findings adding to growing evidence that any benefit of using cats to control city rats is outweighed by the threat they pose to birds and other urban wildlife.

Image credit: ©stock.adobe.com/au/alcatrax1981