The Very Huge Caterpillar

Summer advances and the hot days continue, but I notice the days becoming shorter.

There is a little over a week left of the school holidays, but I’m now back at work.  It’s funny how my blogging activities tend to decrease during holiday periods.


I was coming home from work when I almost collided with this caterpillar.  I say collided because of the size of it – it was certainly in the 80 mm class.

Roadblock ahead…

Just to give you some sense of scale (yes, that’s a de-valuated ¥10 coin)

Identification was simple enough – Google Images is your friend, provided you use the correct search term.  Unfortunately, I wasn’t sure which Japanese word for caterpillar I should use – there is no generic word for “caterpillar – and was successful only on my second choice (and that was dumb luck – the third option was the correct one)


The beast in question is the larval form of Impatiens hawk moth (Theretra oldenlandiae), known locally as sesujisuzume (背筋雀), literally “striped back sparrow”.

It is a member of the family Sphingidae, which includes the Death’s-head hawk moth (Acherontia styx medusa and A. lachesis), well-known to readers of The Silence of the Lambs; and my local favourite, the Pellucid hawk moth (Cephonodes hylas hylas), whose transparent wings and flight pattern cause it to be mistaken for Japanese hornets.


My moth, however, is rather dull and unattractive, except in flight.


The larvae of the Impatiens hawk moth possess a “horn” at the posterior, possibly functioning as a false head.  Lacking spines or stingers, the caterpillar can excrete its foregut contents – sticky and sometimes toxic – to deter predators.  The eye patterns on the side probably also act as a deterrent too.

The nasty-looking horn on the tail-end. Actually, it is completely harmless.


This species feeds heavily on taro and sweet potato leaves – two of the major crops in this area – and has a voracious appetite, making it a major pest for local farmers.

The real “business end” of the caterpillar – this insect is an eating machine.

And anything that size should be considered a hazard for cyclists!

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6 Responses to The Very Huge Caterpillar

  1. Jaclyn says:

    I saw this at saitama Edogawa too. One of them got squashed by a bicycle. I thought it was a butterfly caterpillar :/

  2. Eric Hankin says:

    I just found one in Shizuoka. It’s September 21st, the day after a typhoon hit the area.

  3. cycle says:

    I saw this little guy by the Tamagawa in Ota-ku today!

  4. jpnheo says:

    I’ve seen this type of caterpillar before. It’s camo pattern is quite impressive.

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