Groundbreaking Study Finally Finds How to Control Cats in the City

Mass neutering of cats does work, vast 12-year research project by Israeli scientists in Rishon Letzion proves, and creates new meaning for the word ‘all’

Send in e-mailSend in e-mail
Send in e-mailSend in e-mail
A street cat eating on a path.
A street cat eating on a path.Credit: Idit Gunther/Hebrew University
Ruth Schuster
Ruth Schuster
Ruth Schuster
Ruth Schuster

Street cats. Heartbreaking victims of human expansion and speciesist narcissism? Or, a nuisance and health hazard? Do you weep for their welfare or just wish they were gone? Since cats in the city are controversial in the extreme, it begs asking: Does mass neutering of feral city cats really help control their population?

Yes, if done properly, mass neutering can keep feral cat populations in a city environment under control. So says the first long-term, large-scale, controlled study on mass neutering of street cats, led by Prof. Eyal Klement and Dr. Idit Gunther of the Koret School of Veterinary Medicine at the Hebrew University of Jerusalem. Their results were reported last week in PNAS.

Though street cats are trapped, fixed and returned in many a country, never before has a study of this scope been done.

Street cats eating food placed out for them in Rishon Letzion.Credit: Idit Gunther/Hebrew University

The bottom line: By neutering 70 percent of the feral cats in a city, a contiguous space, no cheating, one achieves a decline in their population, the team concluded. Some rebound does ensue, and the researchers aren’t sure where the point of stability is, Klement explains: that will require more research. But control can be achieved.

Say it with cat food

Let us put aside when we domesticated the cat, or the cat domesticated us, or we simply moved in together. Moving on perhaps 10,000 years from that happy day, today cats live on every continent except, reportedly, Antarctica. They do speak and have even recently been proven to possess hitherto unsuspected social abilities.In Israel’s balmy environment, they thrive. Not all think this a good thing.

Street cats kill rodents and other small animals we appreciate rather more, such as birds and lizards. They relieve themselves where they can, which can create odor and health hazard. Ailurophobes fear them. Street cats are excoriated for raiding garbage and making a mess – but it’s not because they choose to, and their health suffers accordingly. Also, Bram Stoker may have sardonically extolled the “music of the night” by Transylvania’s wolves, but the lupine vocalization may sound positively orchestral compared with cats a-courtin’.

A street cat held by a member of the veterinary study team.Credit: Adir Lotan

So, feelings on “community cats” are intense in Israel. Government sources estimate that Israel has a million feral cats. Israel is also thronged with street-cat feeders, to the annoyance of people unfond of the feline.

The only thing everybody agrees on, from cat lovers to haters, is that there are too many of them. So, managing the population of street cats in temperate regions is important, for their sakes and ours. The method of trapping stray cats, neutering them and returning them to their territory (“TNR”) is widely employed, but there hadn’t been solid evidence that the method even works. Now there is, and it can do. If done properly.

Can’t touch me

The research involved an area of 20 square kilometers (about 7.7 square miles) in the balmy coastal city of Rishon Letzion, involving the relevant (and contiguous) parts of the city – not areas where cats don’t hang out anyway. Asked why they don’t hang out there, the professor says that’s fodder for another study.

The experiment was divided into three equal phases over 12 years: no intervention; mixed-intervention; and full-intervention.

A lady street cat on patrol. Notching the ear is a sign of neutering, when there is an ear to north.Credit: Idit Gunther/Hebrew University

The non-intervention phase means business as usual, which means that the city was fixing some feral cats – say around 20 percent of the population.

The mixed phase involved an intensive program of neutering feral cats in half of the study area, while the cats in the other zones were left intact and served as a control group.

The full-intervention phase involved neutering as many of the feral cats as humanly possible – all in theory. That means, not all. Cat people will understand the following explanation.

“The effort to neuter the feral cats increases exponentially,” Klement says. The problem isn’t waving the scalpel at unconscious beasts; it’s catching them in the first place.

A street cat walks into a trap.Credit: Guy Reibitz
Some street cats are just too streetwise to be caught in a trap.Credit: Idit Gunther/Hebrew University

First of all, if zero cats are fixed, then every one you catch gets “processed,” he explains. But by the time you have neutered 50 percent, then only one of every two you trap is relevant. By the time you reach (say) 80 percent, then only one of every five cats you manage to catch is relevant.

Now: the ones you catch first are the easiest to trap, so gradually you’re left with the hard-core cats that you can’t trap for love, money or even surf ’n’ turf au beurre. They. Will. Not. Get. Into. That. Trap.

The bottom line is that “fixing the whole city” – the full-intervention phase – translated into 70 percent, which is an astonishingly high rate, Klement says.

During the first phase of non-intervention, naturally the cat population did not decrease. Why would it? It increased.

The same happened during the mixed-phase, when “all” the cats in half the chosen city zones were fixed. The population continued to increase, possibly because of male immigration from the untreated half of the city, the researchers surmise. “Intact cats are more territorial than their neutered counterparts. Once they move into a neighborhood with neutered cats, they tend to thrive and take over,” Klement remarks.

There goes the neighborhood? Street cats enjoying their food. Credit: Idit Gunther/Hebrew University
Street cats: friend or foe?Credit: Idit Gunther/Hebrew University

Now: after four years of neutering “all” the cats (around 70 percent), the population of street cats had declined by around 25 percent, he says.

By the way, in Israel, when a street cat is “fixed,” its ear is notched so the poor thing doesn’t get trapped again.

The circle of life

A few fun facts. This whole endeavor, which began in 2010, was the initiative of the scientists, of course, but was enabled by a handsome government budget increase for the Rishon city veterinarian department. Since a lot of surgery was involved, so were subcontractors, who committed not only to performing the trapping and operations, but reporting on each and every cat so treated, and returning each cat to its natural habitat (whatever street it lived on).

Street cats escaping to the seaside.Credit: Gil Eliahu

So what do we have? The first controlled large-scale proof that neutering “all” – 70 percent – of the population of street cats will decrease their population.

Up to a point. Less cats means healthier cats, which means more surviving kittens per litter, Klement explains. So while the population declines, there is a rebound effect, and so goes the circle of life.

Okay. With this new knowledge, is there hope that we can all just get along – cat lovers and haters, cat feeders and their opponents? Probably not. But there can be compromise – there has to be – and Klement has a practical suggestion for how this can be achieved.

It is to control feeding. Cities should create feeding stations for the cats, resulting in less mess everywhere; it will become easier to trap and neuter the cats; and Israel will wind up with fewer obese hedgehogs eating leftover cat food, he suggests. Yes, fat hedgehogs are a problem in Israel.

Everybody would continue do what they please in their own backyard, insofar as they have one. But the dream is that the cities would ban random feeding and set up proper kitty restaurants, and then neighbors would stop feuding (over this at least). The upshot would be fewer street cats in better shape who have survivalist kittens over which the cat-lovers will continue to kvell and the cat-haters will continue to hiss, forever more.

Click the alert icon to follow topics:



Automatic approval of subscriber comments.

Subscribe today and save 40%

Already signed up? LOG IN


Election ad featuring Yair Lapid in Rahat, the largest Arab city in Israel's Negev region.

This Bedouin City Could Decide Who Is Israel's Next Prime Minister

Dr. Claris Harbon in the neighborhood where she grew up in Ashdod.

A Women's Rights Lawyer Felt She Didn't Belong in Israel. So She Moved to Morocco

Mohammed 'Moha' Alshawamreh.

'It Was Real Shock to Move From a Little Muslim Village, to a Big Open World'

From the cover of 'Shmutz.'

'There Are Similarities Between the Hasidic Community and Pornography’

A scene from Netflix's "RRR."

‘RRR’: If Cocaine Were a Movie, It Would Look Like This

Prime Minister Yair Lapid.

Yair Lapid's Journey: From Late-night Host to Israel's Prime Minister