National conservation authorities have called on Cape Town residents, especially those based close to Table Mountain National Park, to contain their cats.

This comes in the wake of a study on local domestic cat predation by scientists from the South African National Biodiversity Institute (SANBI) and the University of Cape Town (UCT). Revealed through Daily Maverick last week, the study has found that the city’s domestic cats kill more than 200,000 animals every year in or near the park.

‘200,000-plus’ wild animals slaughtered in Table Mountain National Park by Cape Town cats each year

Cape Town’s cat population is estimated to be some 300,000-strong. This number, the findings warn, translates into a prey count of some 90 animals per cat each year. Nearly 30-million animals across the city end up in cat claws every 12 months, the scientists announced. The vast majority are indigenous.

Declared by the UN in 2004 as a place of “universal significance to humanity”, Table Mountain National Park is a World Heritage Site designed to protect endemic life, such as the endangered western leopard toad, vulnerable Cape rain frog and orange-breasted sunbird. Either captured by the study’s “KittyCams” or surveys, each of these species was recorded as being mauled by local cats.

Reptile activity coinciding with nocturnal cat hunting times meant that species such as the marble leaf-toed gecko were most popular. It was favoured over mammals and birds. Invertebrates were also recorded on the menu.

“This is an important study that adds weight to a substantial existing evidence base showing that domestic cats have serious impacts on wildlife. [We are] deeply concerned about these impacts on Table Mountain National Park,” South African National Parks, tasked with managing the sprawling reserve, told Daily Maverick.

“SANParks urges cat owners to keep their cats indoors or on their properties, especially in the evenings and at night when cats are most likely to prey on wildlife,” the conservation agency said.

“We have documented caracals preying on domestic cats, and other studies suggest that domestic cats can transfer diseases to wild cats,” it warned.

“Since being hit by cars is an additional risk for roaming domestic cats, keeping them inside in the evenings and at night is clearly the wisest option.”

The paper, first published in the journal Global Ecology & Conservation on 20 July, was co-authored by additional institutions and organisations, including the World Wide Fund for Nature and the Cape Peninsula University of Technology. The culmination of multiple studies over a decade, this was the first African research project deploying KittyCams to record hunting jaunts on film.

The South African paper comes on the back of a slew of recent studies released in Australia, New Zealand, Europe and North America, warning of domestic cats’ burgeoning toll on indigenous biodiversity.

Take us to your leader

Other smaller members of the cat family, such as the blackfooted cat (Felis nigripes), can still be considered wild – they fulfil a natural purpose in the ecosystem. However, as an intensively bred animal over millennia, the domestic cat (Felis catus) is the result of artificial rather than natural selection.

Tamed several thousands of years ago from its origins as a Middle East wildcat, F. catus has drawn such magnificent benefit from its symbiotic relationship with humans that it has come to dominate every continent on Earth, except Antarctica.

Today it is flagged as one of Earth’s 100 worst invasive animals in the Global Invasive Species Database. This inventory is compiled by the International Union for the Conservation of Nature, the international classification authority on threatened wildlife.

Even so, whether as online sources of recreation or real-life companions, many people cherish their feline friends as vital therapeutic cohorts.

The world’s most followed cat on social media, according to the Guinness World Records, is “Nala”, a tabby from the US with hypnotic azure eyes and 4.3-million Instagram followers. Similarly adored, only in this instance for her feline dwarfism and underbite, @realgrumpycat aka “Tardar Sauce” had more than two-million Instagram followers when she reportedly died of a urinary tract infection in May. The ghost of Tardar Sauce continues to dish up posts that attract tens of thousands of likes, even spawning a facemask collection “now shipping worldwide”.

By popular comparison, the Church of England Instagram account has nearly 33,000 followers; the official Vatican account has some 520,000 followers; and Joe Biden, presumptive Democratic nominee for the US presidential race, pulls in at 2.9-million followers.

This places him just 1.5-million fans shy of catfluencer Nala.

Jou ma se pussy cat

Protesting the findings, Cape Town pet lovers have taken to social media, facing off with commenters expressing their concern about impacts on the city’s biodiversity.

“This article unfortunately only encourages the already high animal abuse numbers in SA,” said Marina Rossouw, referring to Daily Maverick’s first report on the study, published on 30 July. “The inferences made from the handful of kitty-cams is simply not reliable. Either way, SA has much bigger problems to solve.”

“I’m not an expert zoologist like you but perhaps you can help me out by explaining your objections further?” countered Mayibuye Magwaza.

“Do you object to their use of Mann-Whitney U tests to compare the amount of prey returned per week, or is your concern more about the data analysis, perhaps the validity of estimating p values with the PIT residual bootstrap method? Either way, I’m sure they’d be very interested in hearing your objections; as scientists I expect they’re keen to improve their understanding and make sure that they get this kind of thing right. I urge you to write to them and help them out.”

Siphili Makhanya added her voice, arguing that “this article isn’t going to make people who aren’t animal abusers turn into animal abusers. Australia has the same problem. South Africa can solve those bigger problems at the same time it solves this one, it’s not a zero-sum game.”

However, Linnae Nockler said that “domestic cats who venture onto the mountain are likely to encounter caracal or get trapped in snares”.

Nockler was sceptical that cats had been found in the park, saying she had “never encountered a domestic cat during a hike anywhere across the peninsula, nor met anyone else who has”.

Magwaza retorted that “they’re small stealthy animals that hunt at night, of course you haven’t seen them”.

“I DON’T HAVE ANY CATS,” Tarryn Green stated. “But I do think that cats are way more eco friendly than rat poisons which happen to kill a LOT more wildlife and especially owls and other birds of prey.”

“Stop demonizing what you don’t like,” pleaded Evelyn Wiehahn. “Doves and wagtails walk right past my cat in the garden. Even cats evolve. Maybe you should too.”

Study co-lead author Colleen Seymour told Daily Maverick that she questioned claims that cats were eco-friendly forms of rodent pest control, pointing out that the research’s native catches outweighed pest samples: for every rat or mouse killed, nine indigenous animals were also removed.

“Cats are kept at densities far higher than those at which natural predators occur – about 300 times denser. Such predation is unlikely to be sustainable,” said Seymour, a SANBI researcher affiliated to UCT. “An owl or mongoose in the garden would be far preferable.”

UCT research associate Robert E. Simmons, also a lead author on the study, added that “typically predators will move out, switch to other prey, or die off as prey numbers diminish. Domestic cats don’t do that. They stay and they continue to kill whatever they can find. This will suppress populations recovering after the lean dry season.”

‘Rates rebates for good stewardship’

According to Justin O’Riain, another author participating in the study, people living near the park are “extremely fortunate to have a biodiversity treasure on their doorstep, but that does come with costs and responsibilities. Costs include wildlife incursions and the threat of fires.”

On the other hand, he said, “responsibilities include preventing domestic animals and exotic plants from entering the park”.

He noted that domestic and feral dogs also impact wildlife not only “directly, but indirectly, by displacing them from areas that they frequent, with and without their owners on the mountain”.

O’Riain, a researcher with the Institute for Communities and Wildlife in Africa, recommended establishing a buffer zone around the park that would encourage nearby residents “to become stewards of this UNESCO world heritage site”.

Stewardship, he suggested, could involve:

• “Not having a cat if you live on or near the urban edge; restricting it to an outside catio [enclosed cat patio]; or keeping it in at night when hunting wildlife is more likely;
• “Cultivating native plants;
• “Smoothing the transition from park to city for birds and insects;
• “Not having baboon and porcupine attractants, including compost heaps, fruit trees and vegetable gardens; and
• “Not using pesticides and herbicides that harm flora and fauna.”

“If good stewardship resulted in a rates rebate or a free/discounted Wild Card, then residents could be incentivised to make changes. With that, they could improve the lives of the animals, plants and people inside and outside the natural/urban edge,” he said.

Ross Wanless, who was not involved in the study, recommended effective trash management to reduce the need for cats as mousers and, by implication, help endangered species. Wanless is a Cape Town-based ornithologist who has done extensive modelling of cat predation in island ecologies.

Integrated pest-management specialists in South Africa also offer natural solutions, such as boxes or “tyre nests”, which attract owls feeding on rodents.

‘Restrict cat ownership around protected areas’

Meanwhile, SANParks has indicated it is considering regulations to intervene in the scale of predation, predicted by researchers to grow as the city’s human inhabitants expand, and thus also the closely allied cat population. Up by some one-million residents over the past decade, the number of people living in Cape Town today stands at 4.6-million.

“We are sensitive to the value of cats for human well-being, especially during lockdown. But while cat owners have a clear voice, biodiversity often does not,” SANParks said.

The agency said its “role is to protect biodiversity, including the vast numbers of animals that domestic cats prey upon. We strongly support initiatives to minimise wildlife impacts from domestic cats. This includes investigation of restricting cat ownership along the boundaries of protected areas.”

The City of Cape Town’s mayoral committee member for spatial planning and environment, Alderman Marian Nieuwoudt, said that “the City notes the findings with interest”.

She added that the City “is fully supportive of using sound scientific research and best practice from around the world to try and manage the impact of domestic cats on our indigenous fauna”.

Urging residents to heed the authorities’ call, Simmons invoked the ‘C’-word several times – a trope not entirely unfamiliar to locals.

“Caracals, cars and contagion might be the big three ‘Cs’ for cats,” he said. “The City of Cape Town could reduce the present limit of four cats per household to two or even one. We learned of a person who has nine cats in their house.”

That, he said, translated into a possible fatality rate of “over 800 prey per year” from one household alone.

“I personally don’t think there is any moral dilemma here,” Simmons added.

“Cats kill massive numbers of wild animals, unnecessarily, and we are an intelligent enough species to do something about it. As the green Mother City, I think Cape Town can lead the way here.” DM

• The Royal Society for the Prevention of Cruelty to Animals offers recommendations of what should be done if your cat brings home prey: if it is dead, “it is best to dispose of the carcass (ensuring first that the animal is indeed dead) as quickly as possible and without displaying any reaction, as a response may inadvertently encourage more hunting. Never punish a cat for hunting. Should the prey animal still be alive, it is advised to swiftly retrieve the animal to check for injuries. If injuries are present or suspected, the animal should be taken to a vet as quickly as possible for assessment. If this is a regular occurrence, then you should seriously consider containing your cat.”
• For a detailed analysis of the South African study’s results, including a complete prey count and references to international studies, read the full paper here.