Photo/IllutrationNyaa sleeps back at home in Eniwa, Hokkaido, on Sept. 12 after going missing for six days after a strong earthquake that rocked the city. (Provided by the owner)

When a strong earthquake struck Eniwa on Hokkaido, located south of Sapporo, just after 3 a.m. on Sept. 6, a 19-year-old woman in the city awoke to the intense tremors.

After the shaking stopped, which registered an intensity of 5 on the Japanese seismic scale of 7, she noticed that Nyaa, a 2-year-old tomcat, who usually sleeps at the foot of her bed, was nowhere to be seen.

She looked around every corner of her bedroom and found the feline, trembling, in a futon closet. When she picked up the cat to put him in a carrying case, he slipped out of her arms and ran out the front door and didn’t return.

The woman posted missing cat posters at evacuation centers and convenience stores around the city and called for information on Twitter, but to no avail. Nyaa suddenly turned up at her home on the night of Sept. 12, six days after the quake.

“I was really happy,” the woman recalled the moment she was reunited with her pet.

She is not the only pet owner who worried about a furry friend who went missing during the earthquake.

During the first week after the Sept. 6 quake, which registered a magnitude 6.7 in the southwestern part of Hokkaido, about 528.9 million Japanese tweets were posted on Twitter.

Of those, some 790,850 were hashtagged with “Hokkaido earthquake” in Japanese.

The Asahi Shimbun analyzed those 790,850 tweets through artificial intelligence, and found that 10,171 were reports of cats running away from home. More than half were tweeted in the first three days.

After a large temblor, many tweets of missing cats are often posted online, while not many dogs are reported missing.

The Chitose Public Health Center, which oversees three cities including Eniwa, received nine reports of “pet cats that went missing due to the earthquake.” Twenty-two reports of similar cases were received by Sapporo city government’s animal control center.

Of those reported missing, one owner notified the Chitose health center that the cat had returned. Fifteen owners reported the same to the Sapporo animal control center.

No reports of missing dogs were received by either service.

When a magnitude-6.1 earthquake shook northern Osaka Prefecture in June, many tweets of missing cats were also posted afterward.

Japan Lost Pet Rescue, a company that specializes in searching for pets, believes the reason for fewer reports of missing dogs is because they are not as agile as felines.

“There were instances of cats escaping through broken windows and breaking through mosquito screen doors,” said Kazuaki Tajima, an employee of the pet search company.

Tajima said cats that are kept inside homes all the time often do not stray too far. The company usually searches within a 200-meter radius of the point where they went missing. Those cats are often found in the premises of the house, houses in the proximity or places with little foot traffic.

According to the company, there are three things that can help cats find their way home: one is leaving a window or door open; two is scattering cat litter that has the scent of the cat around the house; and three is to leave cat food outside.

However, if aftershocks continue, their pet felines may flee farther.

In the case of the Osaka Prefecture earthquake, videos of cats starting to run seconds before the large temblor struck were shared online.

Akihiro Yamane, associate professor of animal ecology at Seinan Gakuin University, said, “Cats have a keen sense of hearing and their whiskers can also sense a minute shake, so it is possible that they picked up something unusual and reacted to the earthquake before humans did.”

A Japanese saying that "a cat belongs to a house" means that it tends to find its way from its new home to the former dwelling when its owner relocates to a new home, unlike dogs.

“Just as the saying goes, where they live is usually a very important place for a cat,” Yamane said. “Running away from home despite that means they must be exposed to considerable amount of stress there.”

Yamane considers that runaway cats are confused by earthquakes and look for safe places to hide.

Cats like “narrow spaces, like small caves where their ancestors lived, where parts of the wall touch part of their bodies,” he said.

However, as they usually have a good sense of orientation, they return when they calm down and feel safe.

To prepare for the eventuality if they run away, it is important to write a phone number on their collars or microchip them for identification.

“If they look anxious, it is important to care for them more than usual,” Yamane said of pet cats.