10 Most Dangerous Predators in Japan


Here we have listed some of the most dangerous predators in Japan, that you could encounter. It’s highly unlikely, that as a traveller you won’t if you live here and especially in the wild, however, then that’s another story. As always we recommend you proceed with caution if you ever think you are in any danger.  We also recommend you always stick to large groups in the wilderness.

Here is what made our top 10 list:

1. Asiatic Black Bears

The Asiatic Black Bear is called the 月の輪熊 (つきのわぐま or Tsuki no waguma). This species of bear is considered middle-sized and they exist around the Japanese main island of Honshu, plus the smaller island of Shikoku. Males are generally larger than females, tipping the scales anywhere between 60 to 120 kgs. Their female counterparts will weight around 40-100kg. They have been measured to be anywhere from 110-140cm in length.

This species of bear tend to be herbivores, mainly feeding on nuts, berries and grasses. However, there is evidence of them eating livestock or other wild animals. Furthermore, there are reports of the bears attacking humans, and these seem to be increasing in number as their habitats become more threatened by deforestation.

There are large populations of these bears that exist west of Tokyo in the mountain ranges, and also in the Kanazawa peaks. However, bear attacks have been recorded across Japan, so they no doubt exist in many throughout the nation.

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2. Ussuri Brown Bears

The Ussuri Brown Beat is labelled the 蝦夷羆 (えぞひぐま or ezo higuma) in Japanese. This species of bear is seen as a close relative of the Black Grizzly, they populate the areas of the Northern island of Hokkaido. Adult males will carry a general weight of 100-360kg, while females tend to weight approx. 130-180kg. Their average length is little less than 2 metres long, but they have been recorded to grow up to 2.7m tall.

Their diet generally as a herbivore consists of nuts, grasses, berries and insects, but can also extend to animals too. At such a large size, and being one of the largest predators in their habitat, they may at times feed on smaller animals, birds and fish too. Fish tends to form a regular part of their diet during the hotter months of summer.

These bears can only be found in Hokkaido, in the North. However, because of their potential size, they can be considered dangerous to humans, so we recommend you avoid contact at all costs.

3. Japanese Wild Boar

The Japanese Boar or 猪 (いのしし or inoshishi) exists through the main islands of Japan, minus Hokkaido. It has many names that it goes by, including the mountain whale (in Japanese) and white moustached pig. They now inhabit many desolated towns, included the most recent evacuated radioactive areas of Fukushima, and have become somewhat a pest.

The pigs are fairly aggressive in nature and are not scared to attack humans, as documented by many stories and videos. Similar to bears, they are also omnivores meaning they will eat a wide variety of vegetation, nuts, berries, smaller animals and fish.

Their average size is around 1.2 to 1.5m long and weigh around 100kg. Although, larger boars have been sighted. Males are larger than their female counterparts and usually have tusks and are more aggressive too.

In interactions with humans, the wild boars bite and will give chase also. Thus, we recommend avoiding any close contact with these animals.

4. Japanese Mamushi (Snake)

The Japanese Mamushi or Japanese Pit Viper is 日本蝮 (にほんまむし or nihon mamushi) in Japan. It is the most venomous of the snake family that exists in Japan. This kind of snake can be found throughout the country too and likes to make its home in marshes, swamps, meadows and rocky landscapes.

It can grow up to 50 to 80cm in length, and it usually features a black or brown shaped head and a grew or reddish brown coloured body. Its main diet is comprised of mainly rodents, birds and small lizards and so it tends to hide out and ambush its prey. It can also camouflage itself in dense vegetation or thick scrub.

It typically bites on average around 2-3,000 people per year, but thankfully there is an antivenom. Bite victims generally have to be treated in hospital for a week, and then fully recover. However, in rare cases, people may end up in intensive care for severe bites, where recovery can take a lot longer. Unfortunately, about 10 people die from bites annually.

5. The Habu (Snake)

The Habu or Okinawan Habu is also called the 波布 (はぶ or habu). It is a snake that is limited to the Ryukyu islets of Japan. It is considered to be as venomous as the Japanese Mamushi and just as dangerous to humans. However, it is bigger than the latter growing up to over a metre at 1.2-1.5m on average long.

It inhabits the larger of the Ryukyu islands, including Okinawa’s main island, but does not exist on the smaller islets. They are commonly found in old tombs or caves, rocky walls and in the thicker forest areas. This snake is characterised as a nocturnal hunter that mainly feeds on mice and rodents.

It is reported that 2 in every 1,000 people are bitten by a Habu, which is a pretty high rate. Plus, the snake’s venom is highly toxic to boot and can cause disability. Yet, if people receive medical care promptly, they will almost always recover from a bite. Less than 1% pass away, but occasionally some people are left with a permanent disability (around 7%).

6. Giant Centipede

The Giant Centipede or 百足 (むかで or mukade) is a large resilient insect-like creature. It is an aggressive predator and will try to wrap its multiple legs around anything in its path. It can grow up to 20cm long and features up to 21 body sections with a pair of legs attached.

The Centipedes main diet consists of insects, spiders and even scorpions. Moreover, if large enough it will try its luck on smaller animals like mice and lizards too. They tend to look for shelter indoors during the rainy season and are especially active in the summer around the countryside.

This kind of Centipede has venom, which it uses through its jaws to kill its prey. As a result, it will readily bite humans too. Although no deaths have been recorded, if you receive a bite, it is best to visit a drug store to find something to soothe the pain.

7. Redback Spiders

The Redback Spider or 背赤後家蜘蛛 (せあかごけぐも or seakagoke gumo) is a venomous arachnid that arrived from Australia (my home!). It found its way into Osaka, Japan via a woodchip shipment. They have since settled across the country with several numbers spotted across the country. These include places in Fukuoka, Osaka and even Tokyo.

The females can grow up to 1 centimetres long, while the smaller males will only reach 3 to 4 millimetres. The spiders are generally nocturnal animals, hiding during the day and spinning her web at night. They usually feed on insects, but they can also eat small lizards, snakes and other spiders that become entangled in their web.

Redback venom is not lethal but has the potential to cause serious pain and swelling. If the venom does not treated, this can continue for hours or even days. Antivenom can quickly reverse the effects, and usually, patients fully recover in a couple of days. For any bites, we recommend you go to the hospital immediately for treatment

8. Japanese Hornets

The Japanese Giant Hornets or 雀蜂 (すずめばち or suzumebachi) are large insects which prefer mostly the rural areas of Japan. Outside the cities, the Hornets have access to an abundance of trees where they prefer to build their habitat.

They are large in size and can grow upwards of 4cm long with a wingspan of over 6cm. They mainly prey on smaller insects, particularly other hornets honey bees and mantises. When a scout locates a beehive, it will use pheromones to attract other mates before they attack. They like to feed on the bees’ larvae and pupae which they will take back to their own hive to feed their own larvae.

The Hornet’s is very aggressive, especially when provoked. Its venom can be lethal if it stings a victim multiple times. so it is best to seek medical care in all cases. Around 30 to 40 people die from hornet stings each year.

9. Mosquitos

Mosquitos or 蚊 (か or ka) in Japan are another insect that can cause irritation or even spread disease. In the summer season, they come out in force too, especially hanging out around lakes, rivers or even puddles. This is where they lay their eggs. One egg only needs 6mm of water to become active.

They typically grow to about 4-5mm in length and generally active from May to November. You can find them throughout Japan, and especially near any place that has water.

Mosquitos will take blood from any kind of animal, bird or human. One meal is enough for a female to lay up to 300 eggs. They are also notorious for spreading serious viruses such as Dengue Fever orWest Nile Virus.

10. The Japanese Mountain Leech

The Japanese Mount Leech or 山蛭 (yamabiru) are small but feisty little worm-like creatures. These unsuspecting predators are perfectly fine outside of water, where you can find them on land and even up trees. Their innocent appearance, almost like a worm is another misleading factor.

Once they identify a victim they can come somersaulting at you at high speeds. Their fondness of trees adds to their advantage as they use the height to drop onto their prey.

They have several jaws lined with lots of tiny teeth. Once they bite, they will inject you with a compound that acts as an anesthetic, numbing the wound. This prevents you from feeling any pain as they suck the very lifeblood from you. More frightening is their ability to bite through clothing, for example, socks (try not to think about it though).

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  1. The redback spider looks very much like a particular type of spider seen in numerous areas across the United States. Known as the Black Widow. There are several types, but those with hourglass red markings on their underside belly or topside back are fairly common. I always thought that it’s name followed it’s bite. In rare instances it could be fatal, but more likely her bite/venom was painful enough that without prompt treatment, you might wish you were dead, etc. Not at all interested in personally finding out.


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