Dangerous Critters of Iwakuni


dangerous critters of iwakuni

Aaron Pylinski | Community Writer

Warm weather is here and so are the dangerous critters. Friends and co-workers might tell you about their creepy-crawly horror stories. There’s nothing that makes the skin crawl more than hearing about how your friend fell asleep under a cherry blossom tree and woke up in excruciating pain because a Mukade slid up his shorts and bit his inner thigh. Or that time your buddy was at the range, picked up an empty ammo can and stood face-to-face with a Huntsman Spider the size of a softball.

If you’ve been to the Welcome Aboard brief then you’ve probably received the crash course in all forms of wildlife that creep around in Iwakuni. Most people have their fair share of horror stories, to include how impossible it is to kill a Mukade (not to mention how if it feels threatened, it’ll signal its buddies and gang up on you). You’ve probably had the bejesus scared out of you by a coworker about the giant hornets that fly around feasting on honeybees and marking targets for attack. Or you might not know that you are sharing the city with the most poisonous snake in Japan.

Fear not, for dangerous insect attacks and poisonous snake sightings on station are next to none and you have a better chance of getting nipped by your neighbors super territorial terrier than a Tanuki. Don’t get a false sense of security, though because it’s better to be prepared than find yourself running the risk of an emergency room visit due to a painful spider bite.

Here, we’re going to give you an in-depth look at what’s in the area, how to keep yourselves safe, and what you can do in the event of an emergency. Like most things in Japan, we’re going to learn about how these critters fit into Japanese Culture. Although you might get creeped out, don't get scared, get educated on the gnarly wild animals and insects that inhabit our world here in Iwakuni.


Japanese Giant Hornet (aka Osusumebachi)
Danger Level 10+

The Japanese name roughly translates to “giant sparrow bee” and for good reason, these winged frightmares can grow up to almost two inches long. They’re orange and black and their stinger is about a quarter inch long. They can spray a pheromone that will ruin your day by alerting its friends to your location. They don’t only attack humans, they will also attack other bees. Especially if they need to feed their kids. These pack hunting bee murderers locate a honeybee hive, mark it, and signal to their buddies for a full-on fight to the finish. Honeybees hardly ever win. All bee slaying aside, these wasps claim as many as 40 human lives a year, so stay away. Their sting can affect the nervous system and cause tissue damage around the sting site. If you do get stung, wash the wound with clear water immediately and get to a hospital as soon as you can.

Standard Procedure

These insects shouldn't be messed with and should be seriously avoided at all costs. Don’t even attempt to kill these. If you’re out and locate a Japanese Giant Hornet or a nest, avoid it and report it.

Fun Fact

Japanese Giant Hornets can fly up to 50 miles a day, so unless you’re an ultra-marathoner, you’re not outrunning these things.

Japanese Mamushi (aka Nihon Mamushi/Japanese Copperhead)
Danger Level 10

The Mamushi is a mean-looking snake and the most venomous pit viper in the country. Not only is it deadly, it's also quite common. It is recognized by its reddish-brown, pale gray, or yellow-brown background scale color and is covered with a number of irregularly-shaped darker blotches. These blotches have black borders and often have a lighter colored center. Adults are usually between 12-25 inches long. The Mamushi has a triangular shaped head that is usually a pale grey or beige. These colors can vary depending on its environment. The Mamushi can be found in just about any rural environment including meadows, swamps, hillsides, rock outcroppings, and woodlands. Statistically, the Mamushi claims up to 10 deaths a year.

Standard Procedure

Though these snakes can be deadly, they are prolific rodent eaters. If found, don’t handle them. Alert the proper authorities and have them relocated.

Fun Fact

Mamushi are sometimes caught and pickled in shochu or awamori and the concoction drunk as a tonic.

Japanese Lore: Snakes are believed to be the reincarnation of the deceased, especially those people who had a strong presence. On Mt. Odaniyama at Kohoku Town, Shiga Prefecture, where the ruins of the Odani Castle remain, it is said that numerous warriors who died when the Odani Castle was besieged were reincarnated as Japanese Mamushi and continue to guard the castle.

Giant Centipede (aka Mukade or King Mukade)
Danger Level 9

This is the no fear bug of Iwakuni. You know when a centipede of this magnitude and attitude bows up on you, you’re in trouble. So steer clear of these insects at all costs. The Mukade can grow up to 15 inches and have a slender, dark body with tan-colored legs. They have a reddish head with long antennae in front. They eat cockroaches, which are disgusting, and have been known to eat small rodents, too. The Mukade love hiding in shoes, linens, pillow cases, and any other place that is out of sight. If they bite you, you’ll notice, it will hurt and there will be swelling. If a bite goes unattended, it could result in a fever and general weakness. Ask anyone who’s been in Japan for more than a year and they’ll have a Mukade story about how bad the bite is or how impossible they are to kill. The good news is that there are no recorded incidents of people dying from a Mukade bite.

Keep Mukade away from your home with Chikusakueki 竹酢液: Bamboo vinegar liquid. This will create a line that Mukade do not like to cross. Sold at most home centers.

Standard Procedure

This insect is nearly impossible to kill. So handle carefully with grill tongs (or a special Mukade tool that can be purchased in town). Then place the Mukade outside away from your house.

Fun Fact

If you attack this insect, they’ll signal to other Mukade in the area and they will come to its defense. Super, happy fun time!

Japanese Lore: Mukade are often used as symbols of evil in Japanese art.

Golden Silk Orb Weaver (aka Jorou Spider)
Danger Level 8

We all have that slightly big, slightly scary friend to take out with you on the weekend just in case things get a little crazy. The Jorou Spider is that friend in the bug world. They can grow up to two inches (not including legs). Females are usually larger than the males and they are pretty hungry after mating so she eats her partner. If bitten, the bite is mildly venomous, similar to that of the black widow but is less potent. A bite typically causes redness, pain, and blisters around the bite. Allergic reactions are rare but can cause shortness of breath and muscle cramps. If bitten, seek medical assistance immediately. The Golden Silk Orb Weaver is a very beneficial farm and garden insect. It eats most flying bugs and occasionally eats beetles and dragonflies. These spiders can be found in trees or overhangs on the outside of buildings.

Standard Procedure

Unless you feel directly threatened by these spiders and they aren’t hindering your day-to-day routine, it would benefit to keep them around so they can eat the insects we dislike more, mosquitoes.

Fun Fact

Fishermen are known to use the Golden Silk Orb web as nets to catch fish. Something equally cool is that it secretes a chemical in its web to ward off ant attacks.

Japanese Lore: In Japanese folklore, Jorōgumo, a type of yōkai, is thought to be a Golden Silk Orb Weaver (Jorōu spider) which can shapeshift its appearance into that of a seductive woman. Guys beware.

Keep spiders away from your home using the following:
1) Essential oils (eucalyptus, citronella, lavender, peppermint, tea tree, cinnamon, citrus, cedar), Spider repelling herbs (lavender, lemon balm, lemon verbena, lemongrass, mint).
2) Sprinkle diatomaceous earth (DE) along the areas where you see bugs or spiders crawling. Make sure that the DE is distributed evenly, like a thin layer of dust.
3) Nuts! Place chestnuts around the outside of your home, under furniture or on windowsills. Horse chestnuts (Aesculus hippocastanum) or walnuts can also be used.

Yamakagashi (aka Tiger Keelback)
Danger Level 5

This snake looks like it could be a distant cousin of the Eastern Garter Snake but don’t be fooled. Although it is non-aggressive it is dangerous. Its color pattern is olive-drab green with black and bright orange crossbars or spots from the neck down to the first third of the body. Typically, they can grow up to 39 inches long. Its venom-injecting fangs are located in the back of its mouth, making it difficult to inject its venom into humans. They tend to gravitate towards fields and wetlands due in part to their diet consisting mainly of toads and frogs. Occasionally, a Yamakagashi might find its way into your house. Do not attempt to catch this snake and remove it, call the proper authorities. It doesn’t have the typical characteristics of a pit viper with the sinister looking triangular shaped head. It does look like a Garter Snake. But don’t be fooled. If bitten, you will bleed, a lot. Symptoms include continuous bleeding from the bite wound, bleeding from the gums, and blood in the urine. Like I said, a lot of bleeding.

Standard Procedure

These snakes snack on poisonous frogs, so as opposed to killing them, maintain that safe distance and let them be. As interesting as these snakes may seem, they are not pets. Do not handle.

Fun Fact

This snake is incredibly interesting. The Yamakagashi has a gland on the back of its neck which secretes a toxic irritant that is used as a defense against natural predators making this snake both poisonous and venomous. When a female Yamakagashi is carrying its eggs it actively seeks out poisonous amphibians to  absorb their toxins and pass it along to her young.


Huntsman Spider (better known as Ashidakagumo)

Another transplant, these spiders are intimidating and grow to the size of wet-yer-pants proportions. This is a gnarly, nightmare of an arachnid and should not be messed with. It’s an ambush predator. Let that sink in for a minute. Like most ambush predators, it has an innate ability to get the jump on its prey. Hence the name “Huntsman.” Legs and all, this spider can grow up to a foot in diameter. It’s a big furry sonofagun that looks like the sinister creation of a wolf spider and a tarantula mating. Though it may not be poisonous, its bite does pack a bit of a punch. Though they aren’t naturally aggressive towards humans, that doesn’t mean get your buddies together to see who can grab one without getting bit.

Standard Procedure

These guys like to snack on cockroaches, so if you see one, maybe keep it around so it can keep those nasty roaches at bay.

Fun Fact

Luckily, it is not poisonous to humans, but its bite will hurt like the devil.

The Japanese Racoon Dog (aka Tanuki)

Cute? Yes. Wild? Most definitely. The Tanuki sometimes is confused as a Raccoon or a Badger, but it is neither. It is actually a wild dog. It has color variations similar to that of a Raccoon with light and dark variations in the body and a Raccoon-like face. Tanuki typically live in burrows and come out at night. They’re scavengers that rummage through trash and chew through wires.

Don’t leave trash or food out or attempt to feed, and Tanuki shouldn't be a problem.

Standard Procedure

Call the trouble desk. A good majority of the time you aren’t going to have a run-in with a Tanuki, but if you do, alert the proper authorities.

Fun Fact

In old Japan, Tanukis were hunted for their meat, fur, and their skin which was used as a malleable sack for hammering gold into gold leaf.

Japanese Lore: Appears often as shape-shifters with supernatural powers and mischievous tendencies.

Cockroaches (aka Gokiburi)

Japan is home to some of the biggest and dark-colored roaches in the world. Most roaches prefer warm, humid environments as well as filthy living conditions, so keep your residence clean to stay relatively roach-free. They usually grow up to an inch long and can fly, though they usually prefer to crawl around. They are not known to bite but don’t put it past the world's most prolific evolver to grow a set of teeth and nibble on your toes while you sleep.

Gokijet is a chemical spray and can be found at most hardware stores. There is also Goki Barrier that does exactly what it says. A more natural roach killer is Mushi-San Bye-Bye, which is a general bug killer. The best deterrent is cleanliness, though.

Standard Procedure

Dispatch them appropriately.

Fun Fact

Cockroaches are repulsive and can carry up to 33 different types of bacteria, six kinds of parasites, and at least seven pathogens.


Japan has no shortage of the winged bloodsuckers we all have grown to despise. Mosquitoes around dank, wet areas are prolific and shouldn’t be taken lightly. Japanese Encephalitis is a disease spread through mosquito bites. Symptoms include fever, headache, vomiting, confusion, and difficulty moving. If untreated, later symptoms include swelling around the brain, coma, and death.

Keep mosquitoes away with the Japanese “mosquito coil”. This incense is very common in Japan as a form of indoor/outdoor mosquito repellent, the smoke being irritating to mosquitos and other types of insects as well. A product that is labeled “kayoke” will repel mosquitoes. A product that is labeled “katori” will kill mosquitoes. Building a bat house is also an alternative, nature-friendly option.

Standard Procedure

Eliminate them. In the words of Arnold Schwarzenegger:
“Do it. Do it now!”

Fun Fact

Mosquitoes are attracted to the carbon dioxide, lactic acid and octenol found in our breath and sweat. They may have a preference for beer drinkers.

Bats (aka Koumori)

The Japanese House Bat is most common in this area of Japan. It usually feasts on beetles, mosquitoes, and other flying insects and prefers to roost under roofs of old buildings. They are able to get into houses, which can really creep people out. Adult bats usually grow up to two inches in length and have a wingspan of three inches.

Standard Procedure

Cases of bats with rabies in the area are low. They eat mosquitoes, so there is a benefit to keeping them around.

Fun Fact

Bats are not blind. Many bats can see quite well and some species can even detect ultraviolet light.

Japanese Lore: In the past, the bat was viewed as a good-luck symbol, and its image was often used in pottery, sword hilts, and kimonos.



This is an albino variation of the Japanese Rat Snake and is considered a national treasure in Japan. Seeing one of these white snakes in the wild is like seeing a leprechaun.

Japanese Lore: The Shirohebi is a good fortune summoning guardian diety of the home.

Red Fox:

Not the actor, God rest his soul. No, an actual Red Fox. They have been occasionally sighted on station, but don’t pose any real threat. That doesn’t mean make a pet out of them. They’re no different than the Tanuki in the respect that they are wild animals.


There are roughly 30 types of Cicadas in Japan. Typically these noisy insects signify the coming of summer. The Cicada larvae are pretty creepy looking, more so after the adult tears away leaving a hollow exoskeleton. Cicadas in large groups can produce sounds up to 120 decibels.

Now that you’re terrified to death to go outside during the summer months, know that with the proper education and preventative measures, such as the variety of repellants and traps available at the MCX, you’ll reduce the risk of serious injury and can enjoy your time in Iwakuni. The chances of a run-in with these pesky critters are low, and time should be spent worrying more about what to do on the weekends. Ultimately, these freaky-deaky things that crawl in the night shouldn’t be handled and when in doubt always call a professional.