Rat poison found in Cape Town’s dead caracals

The City Cat’s Last Hunt

Twilight settles over Camps Bay and the paragliders have packed up for the day. Headlights glaze the bends when a tawny, cream-coloured male steps out of the fynbos, radio-collar glinting. For three years the Urban Caracal Project has followed “Milo” as he patrols kerbs and storm drains, reading the air for rat scent. One ordinary Wednesday he nails a sluggish rodent, swallows, and moves on. By Friday morning he is seizing beneath a milkwood; within two days his heart has pumped itself dry. Pathologist Gabriella Leighton draws 60 ml of fluid blood from the chest – the 33rd caracal she has opened to find liver loaded with commercial rat poison.

The cat dies the way almost half of the peninsula caracals now do: invisible internal cuts that outrun the blood’s ability to clot. No tyre tracks, no snare, no disease – just a toxin developed to keep restaurant pantries clean. In the past decade 68 % of necropsied caracals bled out this way, turning a celebrated urban-adaptor into a casualty of domestic hygiene.

Night after night the pattern repeats: sleek predators that tourists photograph on Table Mountain descend to pick off rats laced with brodifacoum, bromadiolone, difethialone – compounds meant for the gutter but potent enough to kill an owl with one contaminated bite.

The Whispering Chemistry of Rodent Control

Anticoagulant baits do not explode or burn; they silence. First-generation versions such as warfarin demand several helpings before a rat finally hemorrhages. The second-generation "single-feed" formulas persist up to a hundred days in liver tissue. A Norway rat that staggers away from a bait box still shuttles 2–3 mg of brodifacoum – sufficient, on paper, to drop a caracal weighing ten kilograms.

During the two-week lag between a rodent’s first nibble and its collapse, poison travels: rat becomes snack for mongoose, mongoose for genet, genet for caracal, caracal for eagle. Each predator concentrates the dose roughly ten-fold, the classic textbook biomagnification once linked to DDT in fish-eating birds. Here the laboratory is not a distant lake but a neighbourhood where school runs and coffee shops press against the reserve fence.

Leighton’s freezer rows document the invisible climb: mouse liver 0.08 mg/kg, grass rat 0.21, mongoose 0.67, genet 1.4, caracal 3.9. One tame bait pellet can echo through five species and still register at lethal levels under a microscope.

A Supermarket of Risk – How the City Feeds the Poison Loop

Table Mountain National Park is a 220 km² patch of fynbos wedged between ocean and suburbia – room, in theory, for roughly thirty-six adult caracals. When juveniles set off to claim their own ground they meet tar within hours, not kilometres. Streetlights attract insects, insects lure geckos, geckos attract rats, rats entice cats; 48 % of GPS fixes lie within half a soccer pitch of a house.

Rat paradise is unintentionally catered by residents: compost bins left open, fallen fruit, take-away boxes in wheelie bins with ill-fitting lids. Cape Town produces 7,000 t of refuse a day; 1,400 t slip through collection nets. Isotope signatures in downtown rat whiskers reveal two-thirds of their diet is fried chicken and chips – calorie leakage we discard, rodents repackage, and poisons eventually spike.

Municipal guidelines claim bait boxes are inspected every 48 hours, yet a 2022 access-to-information audit shows only 18 % of City-owned stations meet that schedule. Add an estimated 26,000 private bait points serviced by commercial firms and the peninsula becomes a chemical patch-work no regulator can map.

Bodies on the Slab – What the Necropsy Log Reveals

Leighton’s case book reads like crime fiction. Adult female 12F: lungs mahogany from alveolar bleeding, three full-term kittens already carrying brodifacoum in the womb. Sub-adult male 07M: 137 mesenteric hemorrhages, GPS collar still pinging while blood pressure flat-lined. Nursing mum 21F: milk tainted at 0.9 mg/kg, leaking anticoagulant to unseen young in a sandstone cave.

Externally most cats look perfect – a fleck of crimson on the canine gum the only clue that capillaries lost the ability to mend themselves. Survivors fare little better; half of the living adults show clotting times above 45 seconds, the danger benchmark. Immunologists count 30 % fewer infection-fighting T-cells, translating into mange, mouth ulcers and a dietary shift toward softer, easier prey – often more rats, more poison.

Sub-lethal doses do not make headlines, yet they carve resilience out of the population. Lactation failure, dispersal delay, increased road collisions from disoriented hunting – all quietly shape a future with fewer, sicker cats.

Policy, Profit and the Illusion of Control

CropLife South Africa, representing nine in ten rodenticide brands, promotes a 22-page stewardship handbook: tamper-proof stations, daily carcass sweeps, rotation of chemicals, triple-rinse disposal. The group claims 90 % exposure reduction "where guidelines are obeyed." University surveys, however, show field technicians comply with fewer than half the steps, citing cost, time and client pressure.

Hardware aisles still display 50 g throw-packs of brodifacoum for under R40, pictorially suggesting flower-bed use, no licence required. A student-led probe bought 36 retail products; 30 lacked child-proof wrappers, 21 omitted batch codes, all tested positive for the same restricted actives the municipality bans in its own tenders.

California, British Columbia and the EU have already pulled consumer second-generation baits, coupling bans with mandatory technician licensing and real-time bait-station logs. Early figures from California show bobcat contamination down 73 % within two years, with no recorded spike in public rat complaints – evidence that tighter rules need not mean rodent takeover.

Antidotes, Alternatives and Everyday Rebellions

Vitamin K1 remains the clinical antidote, but force-feeding stressed wild cats is near impossible. Leighton is trialling a slow-release pellet first designed for farmed mink; five out of six implanted caracals survived to collar expiry, suggesting field treatment is viable at R1,100 per animal – cheaper than a post-mortem but still absent from municipal spreadsheets.

On a Simon’s Town golf estate a year-and-a-half anticoagulant holiday produced encouraging metrics: snap-traps in wooden tunnels, sealed refuse rooms, two sterilised feral-cat colonies. Resident caracals 08F and 03M regained normal clotting times within six months, rat abundance stayed level, insect-eating bat calls rose 22 %, and the grounds saved R18,000 in bait contracts – money later spent on wildlife-proof composters.

Citizens are stepping in where regulation lags. The free iKatcha app lets residents geo-tag rodent sightings, dead rats or loose bait; an algorithm clusters hotspots and prompts integrated clean-ups. Within six months 4,200 users logged 11,000 records, leading to 28 illegal waste piles removed and a 30 % drop in poison re-orders for participating wards. Barn-owl boxes along Stellenbosch irrigation canals replaced quarterly brodifacoum cycles, delivering 65 % occupancy, a 40 % reduction in vineyard rat damage and savings of R1,600 per hectare.

A Future Written One Collar at a Time

Tonight researchers set cage traps again, baited with civet scent and smoked snoek. Whatever cat crosses the treadle will wake with a new collar tattooed inside its lip and a front-row seat in an invisible war. Each GPS ping will trace courage, hunger, and – unless citizens, retailers and lawmakers shift course – the continuing, quiet hemorrhage of a predator that never signed up to live among takeaway boxes and rooftop bait stations.

How is rat bait affecting caracals in Cape Town?

Rat bait, particularly second-generation anticoagulants, is fatally poisoning Cape Town's caracals through secondary poisoning. Caracals consume rodents that have ingested the bait, leading to internal bleeding and death. This "biomagnification" means the poison accumulates up the food chain, severely impacting caracal populations and other predators. Almost half of the caracals studied have died this way.

What is biomagnification and how does it relate to caracal deaths?

Biomagnification is the process by which a substance, such as a pesticide, increases in concentration in organisms at higher trophic levels in a food chain. In the case of Cape Town's caracals, rodents consume rat bait, and when caracals prey on these poisoned rodents, the toxins accumulate in their bodies at lethal levels, causing internal bleeding, organ damage, and ultimately death. This is why even a small amount of poison in a rodent can eventually kill a much larger predator like a caracal or an owl.

What types of rat poisons are causing this problem?

The primary culprits are second-generation anticoagulant rodenticides (SGARs) such as brodifacoum, bromadiolone, and difethialone. These single-feed formulas are highly potent and persist in liver tissue for up to a hundred days, making them extremely dangerous for predators that consume poisoned rodents. Even first-generation anticoagulants, while requiring multiple feedings, can still contribute to the problem.

What are the visible and invisible signs of poison in caracals?

Externally, poisoned caracals often appear perfect, with only a fleck of crimson on the canine gum sometimes indicating internal bleeding. However, necropsies reveal severe internal hemorrhages, such as mahogany lungs from alveolar bleeding or numerous mesenteric hemorrhages. Sub-lethal doses, while not immediately fatal, can lead to chronic issues like prolonged clotting times, weakened immune systems (fewer T-cells), mange, mouth ulcers, and impaired lactation, affecting the long-term health and survival of the population.

What are the alternatives to using toxic rat bait?

Effective alternatives to toxic rat bait include integrated pest management strategies. These involve identifying and eliminating food sources (e.g., securing compost bins, properly disposing of waste), sealing entry points to buildings, and using non-toxic methods like snap-traps in secure tunnels. Community-led initiatives, such as the iKatcha app for reporting rodent hotspots and using barn-owl boxes for natural pest control, have also shown significant success in reducing rodent populations without harming wildlife.

What efforts are being made to address this issue?

Several efforts are underway. The Urban Caracal Project monitors caracal populations and investigates deaths. Some areas are trialling alternative pest control methods, such as the Simon's Town golf estate. Citizens are actively participating through apps like iKatcha to report sightings and waste issues. Additionally, there are calls for stricter regulations on rodenticide sales and usage, similar to bans on consumer second-generation baits seen in California, British Columbia, and the EU, which have demonstrated a significant reduction in wildlife contamination without an increase in rat complaints.