Bat Caves in Japan: Tread Carefully

Bats may be known as spooky flying mammals that come out only in the evening, or as pests to others. Because the media have portrayed them in horror movies as creatures of the night, they don’t get as good a reputation as another mammal would with humans. Then again, they have just as much a right to our respect as other animals do.

When some bats hibernate, they tend to occupy caves. If you visit the cave during the right time, you will get to see the bats hibernating first hand. There are many caves around the world that are famous for being the favorite sleeping space for bats, and some of them are in Japan.

But first, it’s important to understand the animal behind the phenomenon of hibernating in these enclosed, naturally occurring spaces. 

What Is A Bat?

A bat is part of the Animalia kingdom, filed under the Chordata phylum, Mammalia class, Scrotifera clade, and Chiroptera order. “Chiroptera” is an ancient Greek word, combining the words “cheir”, which is ancient Greek for “hand”, and “pteron”, which means “wing”. Put together, you have the indication of a hand-wing, which is exactly what the wing of a bat looks like an outline of when it is outstretched. 

If rats hold first place in being the most populous mammal, bats hold second place. 20% of mammals are made up of this species. Under that species are two main suborders; bats that echolocate (Microchiroptera), and megabats that consume fruits (Megachiroptera). Most (70%) of bats eat insects. Other bats eat fruits, while few of them feed on other animals such as fish, others, sometimes, on blood. 

Differences in Name and Species

Just because a bat is classified under the Microchiroptera, or microbat suborder, does not mean that it is smaller than a species under the Megachiroptera, or megabat suborder. They are completely unlike each other in the sense that the microbat has an ability over the megabat; and that is being able to detect the patterns of their outside environments by giving off a sound that is high pitched, which then bounces off their given surroundings – also known as echolocation.

Megabats have forelimbs, while microbats don’t. The ears of the microbat are also shaped differently than that of a megabat, as megabats are ring-shaped, and microbats aren’t. Microbats cannot see at night so they use echolocation to navigate, while megabats have great eyesight. Microbats have a wider range of choices when it comes to their diet, unlike the megabat, which only consumed pollen, fruits, and nectar. 

How Do Bats Contribute to the Ecosystem?

The answer to this question depends on what kind of bat is in question. Some bats that naturally disperse plant seeds, others pollinate flowers, while some bats balance the population of pests with their appetites. No matter what role they play, they play a large importance in continuing and balancing the cycle of the ecosystem that they exist in. 

Where are Bats Found?

Bats are versatile mammals, so they thrive in almost any climate, except for those that stay very cold throughout the entire year. Because they can fly, they have reached many corners of the earth with different terrains, varying their adaptation to the environments they end up in. 

Some bats choose where to dwell depending on the season. Those that live in temperate zones usually hibernate during winter. They can be found anywhere from forests, deserts, caves, mountains, by the sea, to structures built by humans. If they have a warm place to roost, and an area where they can forage for food, they are more than comfortable living there.

Bats in Japan

A common kind of bat in Japan is called the “Japanese house bat”, scientifically referred to as the “Pipistrellus abramus”, or Japanese pipistrelle. These bats love roosting in buildings and houses that have been left behind. Under the Chiroptera order, it belongs to the “Vespertilionidae” family, in the Pipistrellus genus. Its species is formally known as P. abramus.

To put in layman’s terms, the Japanese house bat is a vesper bat, which is under the microbat suborder. This bat, when fully grown, is about 3.6 to 4.8 centimeters long, with a single wing span of 3.2 to 3.6 centimeters, and a tail measured to be 2.9 to 4 centimeters. This bat eats all kinds of bugs, moths, beetles, and flies. 

Aside from being found in Japan, this vesper bat can also be spotted in areas of Taiwan, China, Korea, and others East Asian countries.

The Etymology of the Japanese word for Bat

As for what the Japanese refer to bats, they are called “Koumori”. The reason bats are named koumori is debated; some argue that it originates from the Japanese word “kawahari”, which pertains to the skin being stretched in between bones. Others say that it could possibly have come from “kawamori”, defined as protecting rivers. Perhaps a more sensible option would be the that its name was patterned after the word “kawahori”, - a mosquito eater. 

How the Japanese View Bats

The Japanese had borrowed quite a bit of culture from China, who revered bats very much. Bats are deemed lucky to the Chinese, so for a long time, the Japanese saw them in a positive light. In fact, you could say that in Japanese culture, bats were relatively popular. 

Bats in Japanese Art

Before Japan was influenced by European outlooks on bats, the Japanese loved bats so much, that they were printed on many day-to-day objects, such as kimonos and pots. Many artists loved using them as subjects for their paintings, too. An example is “Bat Before the Moon”, a Japanese classic, painted by Biho Takashi. It was finished in 1910.

Only when Japan opened its gates to the world and caught up with globalization did it ride the bandwagon of perceiving bats as mysterious, creepy creatures – or an animal that is just to be ignored. The way the Japanese use bats as designs are now associated with themes like Halloween and are no longer in the theme of beholding endearment towards the animal.  

Shifting Perspectives

Slowly, however, this perception of bats being associated with dark and/or scary themes is being changed. Documentaries and literature that shed a more positive and interesting outlook on bats are said to be circulating the information Japanese population, with hopes that it restarts the culture of respecting bats. You may be wondering why it’s so important to promote the awareness of and care for bats – it’s because many of their species are threatened to be extinct.

Disappearing From the Face of the Earth

The bat species that live in Japan amount to 37. 3 of those 37 species are currently critically endangered, which means that, if left uncared for, it has a very high chance to become extinct. It doesn’t end there – another 5 species are on the list of those who are endangered, while one of them is categorized as vulnerable. Add another four species with a label of “near threatened”, and you’ve got a third of the Japanese bat population (13 species out of 37) in danger of ceasing to exist. 

There are two reasons as to why these bats are slowly disappearing. One of them is the ever-growing development of Japan, as technology progresses and their natural habitats are torn down to make way for other land projects. Research shows that another culprit is constant abuse and disturbance that touring bat caves bring. 

Visiting Famous Bat Caves in Japan

Caves, where bats dwell, can be a breathtaking sight when thousands of them are huddled up to hibernate. Japan does have a few of these caves as part of the island’s heritage; one of them is in Mount Kochi on Shikoku island (exact location is undisclosed), another is within Mt. Fuji. 

Fuji Five Lakes (which also holds Fuji Q Highland) has a bat cave called “Saiko Bat Cave” or “Lake Sai Bat Cave”, which is rated 19 out of 100 things to do around the area and a 3.5 out of 5 stars among reviewers. It is a lava tube found in the Aokigahara forest, and to walk through this cave/tube, you need to have helmets. Be forewarned; space gets tight and slippery, so you’ll end up crawling (and might get accidentally kicked by someone crawling in front of you). 

According to a report, no bats in this cave anymore. If you’re looking to see actual bats sleeping, then this is not the place to go. Bats sleep during the winter, which the cave is closed for – from December 1 to March 19. That’s if the bats even choose to hibernate in this cave. Otherwise, admission costs 300 yen. The address is 2068 Saiko, Minamitsuru-gun, Fujikawaguchiko-machi 400-0334, Yamanashi Prefecture. It is open from 9 A.M. to 5 P.M., and its telephone number is +81 555-82-3111.

Other Caves Around the Area

If you’re not one to walk into a bat cave but still want to pop your cave visiting cherry, there are two other kinds of caves that Fuji Five Lakes offers. There’s the Ice Cave, which has different ice formations and stays cold all throughout the year. It doesn’t matter if Japan is going through a sweltering summer, this Ice Cave will still hit the negative zone on temperature readings. In fact, it is so reliably cold that people would use it as a freezer to store ice during the first half of the 20th century. Admission here costs 350 yen.

The Wind Cave, which is notoriously less dull experience compared to the other two caves, also was used in the past as a place to keep food and perishables cool throughout the year. Temperatures around this area stay at a steady 0 degrees Celsius, enough to keep the goods at a temperature to reserve them. It currently contains carts of silkworm cocoons and acorns. Admission costs just as much as the Ice Cave.

If you’re unsure about navigating around the area yourself, bring a map or guide along with you. 

Getting There

The bat cave is located separately from the wind cave and ice cave. To get to any of these caves, you can ride a Retro bus on the Saiko Line, as it goes back and forth from the caves to Kawaguchiko Station. The bat cave is nearer the stop, as it’s in Saiko-Komoriana, which is only 35 minutes away. You’ll have to wait another 15 minutes more, for 10 minutes under an hour to arrive at where you depart to walk to the wind and ice caves, which is at Fugaku-Fuketsu. The wind cave is right in front of the stop, but the ice cave entails another 15-minute walk to the east.

There’s another way to go about it if you want to go straight to the wind and ice caves. You may instead opt for buses that go from Kawaguchiko Station to Lake Motosuko. One way will set you back 650 yen, but you’ll only have to wait 15 minutes in travel time. Take note to stop at Hyoketsu if you want to visit the ice cave and Fuketsu for the wind cave.

Avoid Treading in On Bat Caves Still Being Used

Bat caves are slowly growing in popularity among tourists. Though Saiko Bat Cave seems to be the most commercialized and popular one, there are surely other caves out there that 

A Need to Celebrate Bats

Though Japan has many festivals, it does not have one that venerates bats. It is a species so often overlooked, that giving it a little attention – be it on a trendy shirt design along Shinjuku, or a spot on the local news to help encourage its conservation. Treading in on active bat caves disturbs the habitat of the bats that take shelter in it.

Instead of going inside active bat caves or contributing to its use for tourist purposes, there are many other activities around the country that do no harm to the wildlife or their habitats. You can relax at a themed cafe, go cherry blossom watching, take a dip in an onsen, or trek up a mountain (just don’t leave any trash behind). Bats are best left alone, coexisting with people, but on separate terms.