Scourge of rats eats into municipal cash

The Norway rat - Rattus norvegicus - is proving to be a multimillion-rand headache for South African municipalities.

From Alexandra to Edenvale in Johannesburg, these monster rats have defied mechanical eradication, pest control blitzes and even specially deployed owls.

But despite the urban legend that cat-sized rats have been spotted, Johannesburg's record stands at 700g.

A normal house mouse weighs between 10g and 25g, which means these rats can grow up to 20 times bigger.

So rife is the rat infestation in the city's East Rand township of Katlehong that some residents refer to their neighbourhood as Rat-lehong.

"They are as big as my size nine shoe ... my two big dogs deal with them," said businessman Mlungisi Galawe. "However, other people throw them in the streets after killing them, which means one gets to see many dead rats daily."

The Ekurhuleni municipality, under which Katlehong falls, has spent nearly R5-million a year over the past three years in a bid to keep them at bay.

Ekurhuleni spokesman Lebogang Ramashala said bigger rats were recorded in suburbs such as Edenvale, Rhodesfield, Birchleigh and Birch Acres.

Nthatisi Modingoane, spokesman for the City of Johannesburg , said the most prevalent rat was the "large and robust" brown rat, also known as the Norway rat.

He said pest control operators worked daily to keep the rats under control.

He was unable to say how much of its R2-million pest control budget for the 2013/14 financial year was spent on rats.

Even though the most affected areas in Johannesburg are informal settlements such as Ivory Park, Diepsloot, Kya Sands, Masawawa and Alexandra, Modingoane said the city's rodent control measures extended to all its seven regions, including the suburbs.

The Nelson Mandela Bay metro has spent almost R400000 on "baits and poison" over a five-year period.

The municipality's spokesman, Mthubanzi Mniki, said affected areas included New Brighton, Kwazakhele and Veeplaas, as well as suburbs such as Lorraine and Central Hill.

The City of Cape Town has a slightly smaller budget and spent just more than R2-million on all pest control in five years.

Professor Graham Alexander from the University of the Witwatersrand's animal, plant and environment department said humans had only themselves to blame for the rat explosion.

"We have depleted populations of other species that would have preyed on rats and better controlled their numbers," Alexander said.

Snakes were a "great example" to illustrate his point because people "killed all snakes on sight and then wonder why rats get out of control".

Alexander said it was not unusual for rats to develop resistance to normal rat poison.

The Norway rat, found almost everywhere in South Africa, is the largest member of the mouse family.

They are covered in coarse, brownish fur that is sometimes sprinkled with black or white hair.

He said some rats had white patches on their fur because of interbreeding with local domestic (pet) rats once those got out into the wild.

Professor Chris Chimimba, head of the department of zoology and entomology at the University of Pretoria, said the Norway rat easily reached 500g.

"In Diepsloot, for example, the largest rat caught weighed 542.83g, while the largest rat that was caught in Alexandra weighed 462g," he said.