San Francisco and Oakland combined ranked as the fourth “rattiest” cities nationwide according to recent study by Orkin Pest Control.  

Orkin ranked the top 50 cities with the worst rat issues based on the number of rodent treatments the company performed at each city from Sept. 2016 to Sept. 2017. The ranking includes both residential and commercial treatments.

Chicago out beat New York as the most rat-infested city in the county — a title it’s carried for three years, according to Orkin.  

RELATED VIDEO: Overrun by Rats: Novato woman blames dumpsters for infestation

In August, Mother Jones wrote that the US is infested with rats and, that in cities like Chicago, increased rodent complaints have prompted city officials to sprinkle rat birth control on the streets.

San Francisco has had its own share of rat complaints and has seen a spike in rat sightings in the last five years. In 2017 alone, 848 calls were made to 311, San Francisco's official site for information and complaints.  

RATS IN SF: Rat complaints in San Francisco have surged over the past five years

Other California cities to make the list were Los Angeles (3), Sacramento- Stockton (26) and San Diego (35).  

A giant invasive rodent with the ability to destroy roads, levees and wetlands has been discovered in Stanislaus County.

Weighing in at 20 pounds and measuring 2 feet, 6 inches long, plus a 12-inch tail, the nutria live in or near water. They're also incredibly destructive.

“They burrow in dikes, and levees, and road beds, so they weaken infrastructure, (which is) problematic for flood control systems,” California Fish and Wildlife spokesperson Peter Tira said.

When nutria aren’t burrowing, they’re eating. They can consume 25 percent of their body weight each day in vegetation, but they waste and destroy 10 times that.

Since 2017, more than 20 nutria have been spotted in Stanislaus, Merced and Fresno counties. However, that number could explode if they aren't dealt with quickly. Nutria can give birth to up to 200 offspring each year.

“We have traps out. We’re setting traps. We have trail cameras," Tira said. "We’re really asking for the public's help to report sightings so we can get a handle on the extent of the problem."

Nutria are native to South America, and they were introduced to California in 1899 for their mink-like fur.

Wildlife officials believed they were eradicated from the state in 1978 but now think a colony may have stayed under the radar and only recently reemerged.

Nutria is often mistaken for a beaver or muskrat, but it's identified by its white whiskers, rounded tail and webbed feet with just one toe free.