Domestic cats appear to hunt less when their diets are richer in animal-sourced protein, according to a newly-released study out of the University of Exeter in England.
The study suggests that feeding cats more meat could help reduce their impact on wildlife. Lead study author Professor Robbie McDonald spoke to Sunday Morning about this research, and how playing with your cat more often can also help catch and kill fewer animals.
In New Zealand 1 million cats kill 18 times that number of animals every year, including more than 1m native birds, Forest and Bird says, hence the frequent calls for people to adopt other pets.
Professor McDonald said the UK shares the concerns about cats killing native wildlife even though the ecology of the two countries is different.
In the study the team wanted to ask where does the protein in a cat's diet come from.
"Cats have a really specific set of nutritional requirements. We refer to them as fussy eaters but they genuinely have very specific requirements and some of those are quite hard to provide.
"So we wanted to see if we gave them a meatier diet, where the protein came from meat sources as opposed to some plant sources, whether that affected their behaviour and sure enough it did."
They used a sample of 350 cats in which the cats were monitored beforehand, then studied for a week while they got used to their new diet and then assessed for weeks afterwards.
"Herding cats and herding cat owners is quite difficult."
A premium brand of supermarket cat food was used where all the protein came from meat and it was grain-free. Some owners continued using a mix of dry and wet food.
While almost all cat foods are promoted as "complete" with all the required nutrients, "our hypothesis was that maybe some of the cats that are going out hunting are left wanting a little extra. These cats maybe have some kind of physiological requirement that goes over and above what's in these complete diets."
The researchers haven't established what that is exactly and Professor McDonald said the obvious next steps are to try cats on increased amino acids which are an important dietary component.
However, the researchers are also conscious that, like humans, cats shouldn't be eating too much meat.
"In the end what we're looking for I think is to try and really refine a formula for the cats that go out hunting to try and change their motivation for doing so."
Prof McDonald said the study also confirmed that if owners spend time playing with their cats it can be beneficial, especially if they use a "capture and kill" sequence. One example he cited was using a fishing wand toy which the cat chased and captured and then substituting a toy mouse which the cat could "capture and kill".
"But the bad news for New Zealand perhaps is that the big effect of play was in reducing the capture of mammals and I know that many New Zealanders might like their cat to capture the rats and mice that might be around the house."
The study found that there's no downside to using dry food because good quality ones have a high meat content.
He said the issue of cats killing wildlife has been contentious for years and there has been a lot of research working out how much killing they carry out, but much less work on solutions.
"This sort of compromise where you offer owners alternative ways of managing their cats and reducing predation is pretty rare.
"I like to think we've arrived at something that all cat owners can get behind."