Johannesburg's efforts to curb its rat infestation have largely failed, despite innovative traps and pilot programs. A recent study reveals the dietary habits of local rats, highlighting human food waste as a key factor. City officials insist they remain committed to the fight.
In 2018, a competition in the Msawawa informal settlement near Honeydew pitted the Hamelin trap against traditional city wire traps. The Hamelin, designed like a swing-top dustbin lid that drops rats into a water bucket upon activation with bait such as chicken bone or pap, claimed 81 kills compared to the city's 21 over two weeks.
Despite this success, the Hamelin and the 2014 Integrated Rodent Control Project—piloted in Alexandra with barn owls, education, and traps—have been abandoned. City spokesperson Ayanda Radebe stated, “Rodent Control is a complicated aspect of Pest Control and the Department of Health does its best to deal with the matter. The City is currently looking into developing the approach.” The city's Pest Control Section handles complaints and monitoring, with plans to revise the integrated project.
Rodent exterminator Diederik van’t Hof, who helped design the Hamelin, attributes the issue to poor refuse collection in underserved areas. He explained, “I don’t care what you do in the pretty suburbs, rats will move in from poorer areas because daddy rat holds territory and he chases off his offspring and that is where they will ultimately go. Unless you wipe out that nucleus, you are going to have an endless rat problem.” The trap's non-poison method allowed residents in Msawawa to resume vegetable gardening, though the SPCA opposes drowning as inhumane.
Rats pose health risks, carrying diseases like hantavirus, leptospirosis, salmonella, and rat-bite fever, a problem echoed in cities like New York and San Francisco. PhD candidate Gordon Ringani's University of Pretoria study used isotope analysis on rats from Hammanskraal, Alexandra, Tembisa, and the university's experimental farm. Brown rats dominate Alexandra and Tembisa with grain-based diets from scavenged human food; black rats prevail at the farm; and Asian house rats, new to South Africa since 2011, forage diversely in Hammanskraal.
Ringani noted, “It does indicate that discarded food is the biggest issue here and this is where you find the highest concentrations of rats. So this is what needs to be addressed.” This human food dependency could be exploited to target brown rats effectively.