Get all the latest news on coronavirus and more delivered daily to your inbox. Sign up here.

In parts of some U.S. cities, starving rats have been taking to deserted streets amid the coronavirus lockdown. Some have even resorted to cannibalism in their desperate search for food.

Lockdown-related rat sightings have been reported in a number of U.S. cities, such as New York, Seattle and New Orleans, as well as other parts of the world.

“It is not a case of MORE rats occurring; it is more rat sightings that is occurring but only in some areas,” urban rodentologist Bobby Corrigan told Fox News via email. “Rat sightings are a case of block by block; more rats are being seen in those specific areas where the rats were heavily dependent on commercial food trash of restaurants and stores that have closed since the COVID outbreak.”

THIRD COUGAR CAPTURED AMID CITY'S CORONAVIRUS LOCKDOWN

In a recent tweet, Corrigan, who is based in the New York City area, warned that some panicked rat populations are infighting and killing, dispersing openly and even invading buildings under door gaps.

“Starving rats in these blocks are now wandering both day and night; in different directions, and if they smell food leaking from people’s door gaps, they will try to follow their noses and squeeze below the doors (i.e., enter the property),” he told Fox News.

“Starving rats of course like most mammals will become aggressive and violent, killing and then eating other rats in order to stay alive,” added Corrigan, who is also a consultant at RMC Pest Management. “Rat carcasses are being seen on the streets partially eaten by stronger or other rats.”

AMID CORONAVIRUS CLOSURE, YOSEMITE'S BEARS ARE MAKING THE MOST OF THE PEACE AND QUIET

Corrigan said that while some rats in New York City have resorted to cannibalism, others have not had to change their behavior. If their food source -- such as sloppy trash cans or dumpsters -- has not changed, then there will be no change in the rats. “They will be active at night and remain mostly unseen,” Corrigan said.

CBS reports that rats have swarmed the empty streets of New Orleans in search of food amid the city’s lockdown.

“It’s a difficult time to be a rat,” said Claudia Riegel, director of the city’s Mosquito, Rodent and Pest Control Board, during a recent press conference. “Because the food is limited, they are going to start fighting with each other.”

CHILLING VIDEO REVEALS HOW CORONAVIRUS SPREADS FROM A SINGLE COUGH IN A SUPERMARKET

With an increased number of rats on the street, Riegel also voiced concern for the potential impact on New Orleans’ homeless population. “There are pathogens in these rodents, fortunately we don’t see many of the health outcomes,” she said. “We don’t have very many disease cases that are actually related to rodents, but the potential is there.”

Authorities in New Orleans have used the lockdown to “hit commercial areas hard with pest control,” according to the city’s mayor, LaToya Cantrell.

CLICK HERE FOR COMPLETE CORONAVIRUS COVERAGE

CLICK HERE TO GET THE FOX NEWS APP

As of Tuesday afternoon, at least 1.97 million coronavirus cases have been diagnosed worldwide, at least 584,073 of which are in the U.S. The disease has accounted for at least 123,348 deaths around the world, including more than 22,100 people in the U.S.

Follow James Rogers on Twitter @jamesjrogers