Ferrets have become a successful way of combatting rats in public spaces, Rotterdam local council has said, following a trial started at the beginning of this year.

The council received 1,441 reports of rat sightings in public spaces up to July this year, but the animals are also found in homes. “The nuisance caused by rats is extreme,” Leefbaar councillor Benvenido van Schaik, who initiated the trial, told the AD.

Poison as a method of controlling rats and mice has been banned since 2023 because it can harm birds and pets, and render the rodents immune. A blanket ban on leaving out food for birds has not worked either, he said.

Rat catcher Nico Kraaijeveld and his 10 ferrets have sprung into action a dozen times at different locations in the city, including the Afrikaanderplein, where the ferrets killed 69 rats in the space of three hours.

The ferrets are let loose into holes where they hunt down the rats, killing them or chasing them into a cage in front of the hole, where they are dealt with by dogs. “Rats put up a fight, but the ferrets always win,” Kraaijeveld said.

Not everyone is happy about the method, particularly the part where the dogs kill the remaining rats, Kraaijeveld said. “In the country, people are used to killing animals but city folk are shocked by it,” he said.

The council is contemplating the continuation of the use of ferrets and getting their own “ferret brigade” of one or more ferrets. It is also contemplating a more animal-friendly alternative to the dogs.

But according to GroenLinks MP Mina Morkoç, prevention by investing in more greenery which would attract more natural predators, and a cleaner city, should be the answer.