Indonesia is the fourth most populous country in the world and home to one of the largest urban cat populations in Southeast Asia. In its cities — Jakarta, Surabaya, Bandung, Medan, Bali — free-roaming cats are an everyday presence: in markets, on temple grounds, in residential alleys, outside restaurants and in the green spaces between apartment blocks. Most live without any veterinary care, without sterilisation and without vaccination. The welfare implications are severe, and the public health dimension is real.
How large is the population?
Accurate national census data for free-roaming cats in Indonesia does not exist — as in most countries, no government body has comprehensively counted them. What is known, from the studies that have been conducted in specific cities and from the scale of welfare organisation intake data, is that the population is very large and growing in most urban areas.
In the absence of widespread sterilisation, the reproductive rate of cats ensures rapid population growth. A single unsterilised female cat can produce multiple litters per year, with typical litter sizes of four to six kittens. Not all survive — kitten mortality in free-roaming populations is high — but the net effect is that cat populations in urban Indonesia continue to expand wherever sterilisation coverage is low.
The welfare reality
Life as a community cat in an Indonesian city is hard. Road traffic is the single largest cause of injury and death in urban free-roaming cat populations everywhere in the world, and Indonesian cities — with their density of vehicles, motorbikes and narrow streets — present a particularly severe risk. Upper respiratory infections spread rapidly through unvaccinated populations. Mange, ringworm, parasitic infections and malnutrition are common. Female cats in continuous reproductive cycles are physically exhausted by repeated pregnancies. Kittens born in exposed locations face predation, exposure and accident.
The small network of licensed cat rescue and welfare organisations working across Indonesia's cities does extraordinary work with very limited resources. They take in injured, orphaned and sick cats, run vaccination clinics, conduct CNVR surgeries and, where possible, find responsible adopters for cats that can be safely rehomed. They are chronically under-resourced relative to the scale of the need.
The public health dimension
Indonesia has ongoing dog-mediated rabies in several provinces. Cats can act as secondary hosts in areas with active rabies transmission — they can contract rabies from dog bites and transmit it to humans. The World Health Organization's rabies elimination strategy for endemic countries includes cat vaccination as a component of effective control, alongside the primary focus on dog vaccination coverage.
Beyond rabies, unvaccinated free-roaming cat populations carry a range of pathogens — including toxoplasmosis, ringworm, and cat scratch disease — that present low but non-negligible risks to humans, particularly children and immunocompromised individuals. Vaccination and population management reduce these risks as well as the welfare burden on the cats themselves.
Why humane management works and culling doesn't
The instinctive response to large free-roaming cat populations — particularly from public authorities concerned about disease or nuisance — is often to cull. This approach has been tried in many countries and consistently fails to achieve lasting population reduction. The reason is well-understood: when cats are removed from a territory, unsterilised cats from surrounding areas quickly fill the vacuum. The remaining population, better nourished with reduced competition, reproduces more rapidly. Within months, the population rebounds to previous levels or higher. This is known as the "vacuum effect" in population ecology.
The World Health Organization and the World Organisation for Animal Health (WOAH) both recognise catch-neuter-vaccinate-return (CNVR) — also called trap-neuter-return (TNR) — as the only humane and effective method of stabilising free-roaming cat populations over time. Neutered cats continue to hold their territory, vaccinated animals build herd immunity within the colony, and population growth ceases because no new kittens are being born. Over years and with sufficient coverage, population size declines naturally.
The challenge in Indonesia, as in every country where community cat populations are large, is scale. CNVR works — but it requires sustained, city-scale coverage to show population-level results. That requires funding, trained veterinary staff, trap equipment, post-operative recovery facilities and long-term programme management that most local organisations cannot sustain alone.
What WARN is doing
Indonesia is one of WARN's priority countries for our Global Cat Protection Appeal. Our planned programme is designed to fund the licensed partner cat rescue and sterilisation organisations already doing this work across Indonesian cities — providing the capital support, operating cost contributions and veterinary supply chain access that allows them to expand their CNVR coverage.
We are not building new organisations. We are funding the ones that already exist and already have the local knowledge, the community relationships and the veterinary capacity to do this work effectively. Our role is to increase their reach — the number of cats they can sterilise, vaccinate and care for in a year.
Read the Global Cat Protection Appeal for the full programme plan, or make a donation today to fund our first CNVR surgeries and cat shelter weeks in Indonesia and across the other countries we work in.
Help the cats WARN is being built for
WARN's Global Cat Protection Appeal will fund partner cat rescue and cat shelter capacity across Vietnam, Indonesia, Pakistan, Kenya and beyond — humane catch-neuter-vaccinate-return work, veterinary care for injured community cats, and responsible in-country cat adoption for rescue cats who can be safely rehomed.
Read the Global Cat Protection Appeal for the full plan, or donate today to fund our first surgeries, vaccinations and cat shelter weeks. Every pound helps another rescue cat get a fair start.
