Caught on camera: the cute killer kitties of Cape Town (and everywhere else)

SCIENTISTS say there is little that separates the average house cat (Felis catus) from its wild brethren (Felis silvestris). 

All cats are instinctive roamers and natural predators. They have a strong drive to stalk, pounce, and capture prey. Their ancestors were solitary hunters, and this predatory instinct is hardwired into their DNA. And even though domestic cats no longer rely on hunting for survival, their ancient instincts remain intact. Cats are also “obligate carnivores", meaning they have to eat meat to survive.

Cats don't hunt because they are hungry. They are biologically built to be killing machines. 

Cape Town kitties

In a 2020 paper published in the journal Global Ecology and Conservation, Cape Town researchers reported findings from an investigation of domestic cats fitted with cameras.

They found that a cat kills between 90 and 123 animals a year. And while that might not sound too bad, multiplied by 300,000 — the number of domestic cats in Cape Town — it adds up to 30-million animals killed annually. The most concerning part of this predation, the researchers say, is the high number of native animals killed on the Table Mountain National Park urban edge, which stretches from Signal Hill in the north to  Cape Point in the south. 

The study looked at the cats as two gangs — a “deep urban” gang and an “urban edge” gang that hunts along the borders of the national park. Both caught the same number of animals, but the 2,200 cats estimated to hunt in the park killed more native animals. And the animals most frequently slaughtered were not birds but native reptiles. Mammals were second, followed by invertebrates, birds and amphibians.

The research tracked real-time cat behaviour, whereas previous analysis was based on information from cat owners about kills that had been brought back to their homes. 

The video footage showed that up to 80% of kills were eaten or abandoned and not returned to the cat's residential turf. The paper says predation had not only been hugely underestimated, there had also been a misrepresentation of the type of prey being killed.

Wild at heart

Cats have not been domesticated the way dogs, cows, pigs and goats have. A fascinating study led by University of Leuven geneticist Claudio Ottoni analysed the mitochondrial DNA of more than 200 ancient and modern cats (spanning the past 9,000 years) and found we are essentially still at the dawn of cat domestication. Today's wildcats and house cats are virtually the same, and one of the key characteristics is that wildcats are neither social nor hierarchical. They are solitary animals.

“The domestication process seemingly has not profoundly altered the morphological, physiological, behavioural and ecological features of cats, in contrast to what has been observed, for example, for dogs," the study says.

Unlike dogs, whose bodies and temperaments have transformed radically during the roughly 30,000 years we've lived with them, domestic cats are almost identical to their wild counterparts.  House cats also show none of the typical signs of animal domestication, such as infantilisation of facial features, decreased tooth size and docility. Wildcats are neither social nor hierarchical, which also makes them hard to integrate into human communities.

Killer kitties

Cats do not kill because they are hungry but because killing is hardwired into their ancient wildcat DNA. In this study, cats were deprived of food for 48 hours, then six types of preferred food were provided, with a live rat:

“The food types were commercial beef, fish, and chicken cat foods, salmon, and freshly killed hooded rats, either warm or cooled. Food types were presented in pairs, and preference was determined as the food types eaten most in a one-hour period. After being deprived, the cats were then presented with a choice between these foods in ascending order of preferences and a live hooded rat on separate days. Cats were allowed to eat their preferred food for 45 seconds prior to introducing the rat. In all cases, cats stopped eating, travelled 4ft [1.2m], and leapt off a shelf to attack and kill the rat. They then brought the rat back to the food dish and resumed eating."

The study found that “despite supplemental feeding, domestic cats actively hunt and kill prey". The stark reality is that even that fancy tinned salmon Tinkerbell gobbles up for supper or breakfast will do nothing to stop her from turning into a killer kitty when the chance arises to go stalking and preying.

This explains why cats bring home “gifts".

Global issue

There has been extensive research worldwide — Britain, Australia, Canada, New Zealand, the US, and to a lesser extent Europe — on the effects of “domestic cat predation".

According to the South African National Biodiversity Institute (Sanbi), Felis catus has been implicated in the extinction threat to 26% of bird, mammal and reptile species on the International Union for Conservation of Nature red list and has contributed to the threat status of a further 25%. 

Most of these species are on islands where species have evolved with few or no predators, meaning they have no defences against introduced cats. 

It was always thought that continental species might be more predator-savvy, but the proliferation of scientific research over the past two decades shows this is not the case.

In the US, domestic cats kill between 1.4-billion and 3.7-billion birds and 6.9–20.7-billion mammals annually. And in Australia, nearly 460-million indigenous mammals are thought to be killed by Felis catus every year. 

It seems, however, that feral cats do most of the killing. Researchers from the Smithsonian Conservation Biology Institute (SCBI) and the US Fish & Wildlife Service found that “unowned cats"  — classified as “farm/barn cats, strays that are fed by humans but not granted access to habitations, cats in subsidised colonies and cats that are completely feral" — did most of the damage.

Dr Pete Marra from the SCBI said: “Our study suggests that they are the top threat to US wildlife [and] our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals."

Birds native to the US, such as the American robin, were most at risk, and mice, shrews, voles, squirrels and rabbits were the mammals most likely to be killed.

Emotive topic

Despite the compelling research showing the risks of free-ranging cat populations for ecology and biodiversity, it is a hugely emotive issue, pitting animal welfare activists against those with ecological concerns (I already fear the reader comments).

This highly credible American study found that “free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals". 

It added: “[Yet] despite these harmful effects, policies for management of free-ranging cat populations and regulation of pet ownership behaviours are dictated by animal welfare issues rather than ecological impacts. Projects to manage free-ranging cats, such as trap-neuter-return colonies, are potentially harmful to wildlife populations but are implemented across the US without widespread public knowledge, consideration of scientific evidence, or the environmental review processes typically required for actions with harmful ecological consequences."

Closer to home, the Cape Town “kitty cam" study concluded that “the scale of this predation necessitates conservation options to minimise impacts of cats on wildlife, particularly near protected areas".

Yet in Cape Town, too, animal welfare activists promote trap-neuter-return as a viable way to minimise the impact of feral cats on the fragile indigenous fauna of the Table Mountain National Park, where regular fires put massive pressure on indigenous species. 

What can cat owners do?

So feral cats do the most damage, but the much-loved domestic kitty companion is still hardwired to hunt and kill. 

What can a pet owner do to curb the impact of that hunting instinct? 

This research by the University of Exeter looked at various approaches to “reducing predation of wildlife by cats". 

It evaluated cat bells, Birdsbesafe collar covers (brightly coloured neckties that are said to warn off songbirds due to their unique eye anatomy), provision of meat-rich food, object play and a control group. Seventy-two cats in 48 households in England completed the 12-week trial in spring 2019.

The scientists found that “none of the treatments intended to reduce predation affected cat ranges or distances travelled. While owners might use interventions to reduce predation, restricting outdoor access was the only effective means of reducing cat roaming and associated exposure to outdoor hazards".

The Cape Town study also poured cold water on fitting bells to collars, saying: “The majority of prey in our study area are unlikely to hear a bell and those that can may not associate it with danger.” 

Mitigation

There is an estimated global population of 600-million cats, half of which are thought to be “unowned".

International Cat Care (ICC) is a cat welfare charity that was established in 1958 to “challenge cruelty, ignorance and misunderstanding to effect positive change in the lives of cats".

It says because hunting is an innate feline behaviour, trying to eliminate it “could potentially compromise a cat’s welfare". It does, however, provide a number of suggestions for how  to “reduce hunting behaviour".

Because hunting is not entirely motivated by hunger, feeding a cat greater amounts will not reduce their their desire to hunt, but some studies have found that owned cats are more likely to hunt if they are fed only food scraps, so providing a highly palatable cat food with high meat content is important. 

The average well-fed pet cat hunts for only about three hours a day, compared with 12 hours for unowned, feral cats.

ICC also suggest feeding your cat small, frequent meals throughout the day and night to mimic their natural feeding pattern. Timed feeders or puzzle feeders can be used to help owners who are out during the day.

Cats are inherently neophilic, which means they like trying new foods. If cats are fed the same food repeatedly, they may try to find variety through hunting.

ICC also suggests “short yet frequent play sessions" which mimic a cat's natural predatory pattern. “Choose toys that closely resemble a cat’s natural prey to increase engagement. This provides your cat with an alternative outlet for predatory behaviour and uses up energy reserved for hunting."

And finally: “Consider keeping your cat in at times when prey species are most active, for example, dawn and dusk."

♦ VWB ♦

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