It’s hard to associate Tokyo with anything else besides people, buildings and cars, but a closer inspection of the city and its outskirts reveal otherwise.

From 2014 to 2016, there were sightings of masked palm civets in many of the city’s 23 wards. Public health centers urged homeowners to repair leaky roofs and check for any tears in the walls, as the mammals could use them to access homes.

Bats, meanwhile, appear routinely in parks after dusk in warmer months — during the day they can be sighted in bridge tunnels and under the eaves of old buildings. Raccoons can often be seen in areas outside the 23 wards, especially in residential areas near Mount Takao.

In December 2019, another species of mammal made an appearance: the wild boar (capping the Year of the Boar off in style). Boar sightings were registered in Kunitachi and along the Arakawa River in Adachi Ward, alarming residents. Police officers were mobilized and hunting communities were put on standby.

Dubbed “urban boars” on social media, the swine could become familiar sights in Tokyo in the next few years. As of Dec. 19, according to the Asahi Shimbun, 27 boar sightings had been recorded in Tokyo, a significant increase from just five the previous year. That number may sound high but consider Kobe, which social media users have recently started calling the “city of boars.” In 2018 and 2019, nearly 500 sightings were recorded there.

Boar sightings may have been a fitting way to close out the Year of the Boar but more sobering is the fact that two people were killed in boar attacks nationwide in 2019, while a further 32 were injured.

An estimated 880,000 boars live in Japan and many of them could be moving to urban areas as a consequence of the climate crisis and Japan’s declining population. Analysts say rising temperatures and an increased number of typhoons are wreaking havoc on boars’ habitats, causing them to seek food in residential areas that typically have an abundance of food waste sitting in trash cans. Abandoned farms and crop fields are also boars’ favorite feeding grounds and, with fewer local people to track their movements, the boars pretty much eat their way from the suburbs to more densely populated areas.

On a side note, their plentiful diet appears to be contributing to boars’ average weight. According to the Asahi Shimbun, an urban boar typically weighs three times more than their ancestors of 50 years ago.

Despite their size, boars are more easily dealt with than rats — the zodiac animal of 2020. In the summer of 2019, Twitter was rife with reports of rat sightings in Shibuya and one Family Mart convenience store was forced to close down after customers posted videos of rats scurrying around the premises. “This is getting out of hand,” one Twitter user wrote. “Shibuya is a scary place.”

Indeed, myriad complaints have been filed about rats in the tourist hotspot since 2015, when major redevelopment projects were launched in and around Shibuya Station. As old buildings and sidewalks were demolished, many rats were forced to relocate — often to places that were already crowded with other rats. With nowhere to go, they would brazenly appear on pavements. They also appear to have no regard for beloved landmarks, and there have been unnerving reports of rats brushing up against people’s feet while waiting for friends around Hachiko’s statue.

As Tokyo gears up for more construction and redevelopment in preparation for the Summer Olympics, many rats will be left homeless. One particularly problematic area is Ginza, close to where Tsukiji Fish Market was dismantled in October 2018. Some media reported that as many as 10,000 rodents would relocate following the construction work and there were numerous sightings in 2019 in Ginza, which has a plethora of basement restaurants and bars. Underground eateries are, of course, a natural habitat for rats.

Interestingly, Tokyo is by no means the most rat-infested area in Japan — it ranks fourth on a list compiled by PR Times. Yamanashi Prefecture has the biggest rat problem, while Aomori Prefecture has the cleanest bill of health. The northern prefecture’s low temperatures, wind and the choppy waters of the Japan Sea apparently keep the rodents away.