| 1 | Habu |
Venomous? Yes.
The further south in Japan you travel, the more snakes you’ll find, and the number one snake hub is the island of Okinawa. This is home to the highly venomous Protobothrops flavoviridis, AKA the habu, a symbol of fear in local villages. Habus are common on rock walls, roadsides, riverbanks, and crop fields. They’re known to invade primary schools, forcing terrified teachers to hold back a mob of curious kids. Many schools stock a repellent called “Habu Knock” – a single spray can kill the snake within 15 minutes.
Habu venom is mostly hemotoxic, destroying red blood cells and wreaking havoc on skin tissue, sometimes leaving permanent injuries. On average, 50 Okinawans are bitten by habus per year, mostly farm workers. Habus are known for particularly sharp fangs (with a curved shape), that penetrate deep into the victim.
An aggressive habu will coil up and face the victim directly with its triangular head. Local wisdom states that you should never move a muscle when the snake enters this position, as it will interpret the slightest twitch as a sign of aggression.
| 2 | Japanese ratsnake |
Venomous? No.
The longest snake on the Japanese mainland, the large islands of Honshu and Hokkaido. Japanese ratsnakes (Elaphe climacophora) begin life at 40cm, grow to 75cm after 15 months, and end up at between 140 and 300cm. They’re flexible and inhabit numerous habitats, while their diet is equally flexible.
Japanese ratsnakes particularly have a taste for bird eggs, which they swallow whole and crack open using an extra-jagged spinal column. Like the oriental ratsnake of Thailand, they move quickly through the countryside and climb trees easily; they’re adventurous snakes which move an average of 65 metres per day.
Japanese ratsnakes are also the most worshipped species in Japan. In Ikwada province in south Japan, there’s a rare albino version, which numbered 1000 back in 1925. Farmers dubbed them shirohebi, protectors sent by the goddess Benzaiten, particularly as they cleaned up pesky rats.
By the 1990s, these snowy white albinos had plummeted, and a successful breeding program was established. This is located within an immaculately carved shrine, which features water fountains covered with Japanese ratsnake statues, and a gift shop with albino ratsnake lucky charms (with glowing red eyes.) As of 2005, the albino Japanese ratsnakes had fought back and numbered 953 in the wild.
| 3 | Mamushi |
Venomous? Yes.
Japan’s most feared snake. This killer inhabits most of Honshu, including the countryside surrounding Tokyo. Japanese woods are filled with carved wooden signs warning of the dangers of the mamushi lurking nearby.
The mamushi (Gloydius blomhoffii) measures 40-85cm and bites an estimated 3000 Japanese people per year. Its venom is hard to predict, but the worst bites can cause your flesh to liquify. Mamushis specialise in massive cell death, and also boast neurotoxins which cause drooling and convulsions. Then there’s hyaluronidase; this venom ingredient dissolves the surrounding skin to allow other toxins easier entry.
One deadly feature is that bites are hard to notice, with tiny fang marks that often delay hospital treatment. Mamushis are quite fussy, and stick to leaf litter piles in forests. Consequently, most bites happen on the toes, or on the fingers when eager foragers bend down.
Despite the fear, mamushis are often hunted by the orange-coloured Japanese weasel. They’re also eaten by the far larger Japanese four-lined snake (featured below). The mamushi’s own diet is wide, including mammals, reptiles and amphibians.
| 4 | Black-banded sea krait |
Venomous? Yes.
The signature sea snake of Japan. Black-banded sea kraits measure 70-80cm and have a venom ten times more toxic than a cobra. They’re slow-moving snakes and stick to reef areas, where they lurk in ambush for fish. In Japan, they’re abundant around the islands of Ryukyu, and commonly encountered by fishermen in wooden boats.
Black-banded sea kraits can go 6 hours without breathing. They spend much of the time in water, but stray to land to breed and digest food. Stay on a rocky Okinawa beach for long enough, and you could witness this snake wash up in vast numbers.
The black-banded sea krait commonly appears in Japanese cuisine. It’s the main ingredient of irabu-jiru, a traditional soup believed to restore womanhood. Before preparation, the snake meat is dried fully, becoming rock solid. The meat itself is said to taste like tuna (comments are welcome if you’ve tried it…), and to compliment the snake, the soup contains tofu, seaweed, boiled pork feet, and Japanese taro potato.
| 5 | Japanese keelback |
Venomous? No.
The Japanese name for this snake is Hibikari, which means “only live a day”. However, they’re actually harmless, one of mainland Japan’s smallest and most humble snakes. Japanese keelbacks measure 40-65cm and eat small slimy items like worms, tadpoles, small fish and small frogs. They’re common in cluttered rice fields with farm machinery lying around, but also remote forest paths leading up to a mountain shrine. Their favourite spots are forests with a water source nearby. They spent time on ground, but are excellent swimmers, which commonly dive below to hunt for fish in the shadowy depths, sometimes lurking in underwater rock formations.
Japanese keelbacks are olive to light red. Their bodies have only subtle patterns, but their heads are another story – the mouth area is covered with deeply contrasting jet black lines.
Japanese keelbacks are crepuscular, coming out of their sheltered dens during dawn or dusk – any time the sun is on the horizon. However, they sometimes venture out during grim days of heavy rains. They’re small but common, appearing all over the main Japanese island of Honshu.
| 6 | Japanese four-lined ratsnake |
Venomous? No.
A widespread snake in Japan, and a common neighbour of the tiger keelback, particularly in forests and rice fields. However, this is a peaceful snake, with no venom. Even their constricting skills are relatively feeble.
Four-lined ratsnakes are simple to recognise when out and about, mainly because of their signature four lines. These are black, contrasting against their olive scales, and stretch parallel down their entire body. Japanese four-lined snakes also have oval pupils, versus round pupils for its close Japanese ratsnake relative (both elaphe family members).
This Japanese snake has a particularly flexible diet. A study on Yakushima Island found that its main prey was the Okada’s five-lined skink, but a mainland study found a diet of 96.6% frogs and toads. The main two species were the Japanese tree frog and Japanese gliding frog. On the small Kinksan island, the four-lined ratsnake almost exclusively eats the Tago’s brown frog. With small amphibians, this snake sometimes skips constricting, simply seizing the frog and swallowing it alive.
| 7 | Red-banded snake |
Venomous? Probably not.
The red-banded snake, AKA Lycodon rufozonatus, inhabits a large range in southeast Asia, including Korea and eastern China. However, the subspecies L. r. walli is found only in Japan, on the Ryukyu islands of Yaeyama and Miyako. Red-banded snakes are nocturnal and inhabit forests, but particularly moist river plains. It’s believed to be non-venomous, as early explorers filed it under “innocuous” in their hastily scribbled logbooks. They usually curl up inside their coils fearfully, but sometimes they move in the opposite direction and bite savagely.
Red-banded snakes regularly reach 1 metre, and have a particularly wide diet. This includes birds, reptiles and amphibians, and in 2018, they were spotted eating sea turtles for the first time. 2016 saw a battle with a black-banded sea krait, which had slithered onto a limestone rock slit by the coast. Black-banded sea kraits are slow moving outside their watery comfort zones, and the red-banded snake managed to seize and swallow it. But soon after, it regurgitated the now-dead 88cm snake, having bitten off more than it could chew.
| 8 | Tiger keelback |
Venomous? Yes.
This potentially deadly serpent occupies most of Japan, skipping Hokkaido to the north, but lounging around a large portion of Honshu. Its main diet is amphibians, and like the red-necked keelback of Thailand, this snake has the crafty gimmick of storing toad poisons in its back. When predators make a clumsy grab for them, they release these toxins in a deadly white froth.
Tiger keelbacks also possess their own venom, which is easily potent enough to kill humans. One study scoured the archives for tiger keelback incidents from 1971 to 2020. 43 bites were discovered, less than one per year. Patients who received antivenin had a 100% recovery rate, but 23% of those didn’t died. This included two deaths in 2006 and 2020, both elderly people.
Tiger keelback bites are more common in western Japan, as are the snakes themselves. Fortunately, a specific-specific antivenin has been around since 1985. Originally, it was created by injecting venom into rabbits and goats, and collecting the antibodies, but in the 1990s, they switched to horses, as this was more economically efficient.
| 9 | Thsuhima Island pitviper |
Venomous? Yes.
One of Japan’s deadliest snakes. The Thsuhima Island pitviper is a relative of the mamushi, essentially a stranded island version that slowly got angrier and angrier over time. It lives solely on the isolated Tsushima Island, and only became an official species in 1994. It differs from the main mamushi in several ways: fewer red bands on its body, a shorter head, a missing black spot inside the bands, and a salt and pepper pattern on its belly. The Thsuhima Island pitviper is also a faster moving species.
Likes it mamushi cousin, the Thsuhima Island Pit viper has toxic venom. You might guess that the venoms would be similar, but a study on victims from 2005-2018 found that severe hypofibrinogenemia is one of the classic symptoms. This is when fibrogenin levels fall below 100mg/dl, sending the risk of fatal bleeding to perilous levels. This study covered 72 bites, and when the worst patients were given mamushi venom, no improvement was seen in the fibrogenesis. There was no crossover benefit against the toxins of its cousin. This island mamushi is a unique horror story.
| 10 | Oriental odd-toothed snake |
Venomous? No.
One of Japan’s rarest snake species. This forest snake inhabits almost all of Japan, including the main two islands of Honshu and Hokkaido. It appears on many other islands, such as Shikoku, Kyushu, and even Shiashkotan, one of the Kuril islands north of Hokkaido which formed the old ice age land bridge with Russia. Yet across that vast territory, the oriental odd-toothed snake is only rarely encountered.
It’s a secretive snake, and despite being first discovered in 1880, not much research has been conducted since. We know that it likes to hide under forest mulch, and has a diet consisting of lizards and amphibians. It shares one of its top prey with the Japanese four-lined ratsnake: Okada’s five-lined skink. Other foods on this snake’s menu include the Japanese bullfrog and Japanese grass lizard.
In 2020, an 80 year old Japanese man was ambling round his garden, when he picked up a flower pot. Out from below slithered an oriental odd-toothed snake. The authorities were delighted as the snake was becoming increasingly rare in Kashiwa province (east of Tokyo). Odd-toothed snakes have barely any encounters with native Japanese, let alone tourists, but are assumed to be non-venomous.