People living in the city yearn for outdoor green leisure spaces, parks and meadows have become important facilities for various modern cities.
But these wild fields, covered with grass and trees, can also become natural habitats for many pests, making people overwhelmed.
The Recreation & Parks Department is the city agency responsible for managing and maintaining all parks and recreational facilities in San Francisco, managing 225 parks covering about 4,100 acres.
Traditionally, people have mainly used pesticides for sanitize, but this method is very environmentally polluting and can accidentally injure other animals, so its use is strictly controlled. It needs to be operated by trained personnel according to the manufacturer's instructions, and many drugs are not allowed to be used.
This affects the effectiveness of dealing with many pests, especially those with strong reproductive ability, such as rats.
The usual solution is to install rat traps or clean up the garbage on the grass in time to reduce its food, but the effect is not ideal.
Rat infestations have been a headache for San Francisco's park authorities, especially during the COVID-19 pandemic, when human activity has decreased and rats have gained more living space.
In recent years, San Francisco has begun to take a unique approach to addressing the persistence of rat infestations, which is to feed rats birth control pills.
The drug, called ContraPest, was developed by a company in Arizona called Senestech and contains two active ingredients that help disrupt the mice's ability to reproduce.
Nicole Williams, the company's chief strategy officer, said the drug, known as a "milkshake for mice," is sweet and fat-rich, and is delicious for mice, so it's attractive.
Staff at San Francisco's Recreation and Parks Department say the pill is packed in large plastic bait boxes and placed in places where rats are prone to haunting. As long as there are no other delicious food scraps around, the rats will eat it.
As long as the rats eat it, it will destroy the reproductive ability of the rats and make them infertile for a year, which is the average lifespan of the rats in the wild.
It should keep the rat sterile for a year. "It's great because that's the average lifespan of a rat in the wild," Aparton said.
"Killing rats is only half the battle," senesTech CEO Siegel said. The key factor driving rat populations is the birth rate, which is difficult to kill quickly or sustainably by traditional means, and the most fundamental solution is to reduce their reproduction rate through drugs.
Senestech says ContraPest is harmless to other animals that feed on rats.