Tiger Keelback

The Tiger Keelback or Japanese Water Snake (yamakagashi) is such a beautiful snake, with red and black spots along its body, but it is also venomous. Apparently there are not too many cases of people being killed because the snake is relatively quiet and tries to escape rather than attack. This snake does not have the usual front “fangs” we associate with venomous snakes, but instead has venomous molars (i.e. at the back of the mouth). It also has venom glands located on its neck from which, as an anti-predator mechanism, it sprays poison into its attacker’s eyes. I didn’t know this piece of information until after I researched about the snake, but I didn’t notice anything spray out when I picked it up. I will be more careful next time!!
It took quite a while to catch this snake. I saw one sliding through the grass at the side of a small ditch, but it escaped before I got near to it. Then I spotted another and tried to grab it, missing it by inches. I’m not quite sure how many snakes there were at this location, but there seemed to be quite a few because I made four separate attempts in different places before I finally caught one. It was either several snakes or the same one that popped up in different places along a 50m stretch of the ditch!
This species of snake eats frogs and toads.

Rhabdophis tigrinusRhabdophis tigrinus
Rhabdophis tigrinusRhabdophis tigrinus

Reptilia: Colubridae: Rhabdophis tigrinus
Tiger Keelback or Japanese Water Snake = yamakagashi

12 thoughts on “Tiger Keelback

  1. Hi Nigel,
    Very interesting site you have here. I’m also very interested in nature (especially reptiles and amphibians) and also live in Japan. I’m curious about the imformation you posted about poison glands that spray on the neck of the Yamakagashi. I have handled many of these and I’ve never seen or read about such poison glands. Is it possible that they are a bad smelling scent gland? As they do produce a bad smelling odour that sticks to your hands for quite a while. Would it be possible for you to let me know the source of your research on these glands?

  2. Hi Sean,
    Thanks for your comment.

    I read about this poison gland in a children’s reptile book and checked it on Japanese Wikipedia. Link:
    Sorry I don’t have anything more scientific than this as a reference.

    I don’t know what you’re getting on your hands when you touch these snakes, but it seems like it might be the toxic secretion being described. I guess it’s only bad if you get it in your eyes, so washing your hands might be a good idea (I’m sure you do that anyway!!)

    All the best,

  3. Hi Douglas,
    Thanks so much for this useful information.
    Worrying… I will *definitely* be careful the next time I handle one of these snakes.
    Best wishes,

  4. Hello,
    I’d love to use one of your images in my publication. Please contact me if possible.
    Thank you

  5. Hello Nigel,
    Thank you for the information on the Yamakagashi. I have been watching your site for a while. I first saw it while living in Puerto Vallarta, Mexico, and was researching Japanese Insects. Now I live with my Japanese husband in Fukuoka, but we are moving to Nishimera in Miyazaki, so I figured I should make sure there weren’t any dangerous creatures I should be aware of. Thank you very much for your lovely site. Perhaps someday our families can go hiking together. I would love to go hiking with you guys. Please visit us if you come to Nishimera!

  6. Hi !i just experienced very scary situation, with them.
    You guys said that they don’t attack, but i am sure today we both just didn’t run in the same direction.usually i had seen them dead on the road killed by cars.is my first time to see them alive. the story is funny … drunk too much caffe and was on the middle of my sanpo,so wanted to … i almost did but i saw something on the level of my eyes moving odd left right, very fast.
    start running, you can imagine… was so scary.
    believe me they are very fast.
    the next weird thing was that i wanted to go home but the everytime i step forward the snake rise.
    so i just wait until get lost.
    that very day i saw 3 snakes the same in radius under 1km.
    The scary thing was that i didn’t know how i should react in this kind of situation.No more caffe for me before sanpo if i ever go …
    Location Chiba, katsuura

  7. Hi Mary,
    Yes, we’re very lucky to have so many snakes in Japan! I think that they are amazing creatures and I love being able to find them on almost every hike (or sanpo!) during the summer.
    If you are frightened of something, it’s usually best to avoid running, especially in the mountains, because it’s so easy to fall down and injure yourself. The wait-and-watch technique is fine with these kinds of snake. And, believe me, they want to avoid you just as much as you want to avoid them. But please try not to be scared and please try to admire them as beautiful living things.

  8. Thanks for sharing this great site with the world!!!

    I live in Shikoku and often come across shima hebis. I haven’t seen a yamakagashi yet.

    From pictures on the net, it seems that Yamakagashis look very distinctive from japanese ratsnakes because of the coloration (especially the red on the neck and the strong black and yellow collar behind the head.)

    I was wondering, apart from the obvious coloration and the subtle differences in the shape of the head, is there any other way to clearly distinguish between the yamakagashi and other types of colubridae in japan?….are they rough scaled?…



  9. I think this website is so kool … But i love snakes i have alot of posters of snakes in my room on the wall .

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