Stuffs I have tasted (not in Japan, only in SE Asia):
-insects, many kinds but mainly locusts and red palm weevil larvae, delicious !!!
- Monitor lizard: meat is pretty hard (no special taste)
- snakes: only cobra and python, too hard meat (no special taste)
- snails: excellent
- frogs: excellent
- soup of tadpoles: it was bitter (can not say if it was from frogs or toads ?)
- macaques: hard meat (no special taste)
- wild deer: excellent (was also offered one eye and part of the brain)
- wild boar : excellent (even if gamy)
- coagulated blood from deer or boar, prepared in bamboo node: it tastes like... blood (iron like)
- sharks: excellent
-dogs: sorry to say it, but it was excellent (very soft meat)
- palm civet: nice too.
- forest rodents : all excellent.
also tried sago (nice), wild yam (nice), bamboo shoots (nice), flowers of wild ginger (used as spices, horrible), taro (nice), rice wine (nice),
cassava (nice), durians (excellent), betel nut (did not feel anything lol), hearts of rattans (from soft to very bitter taste depending on the species) and so many other stuffs I can't remember now.
Yet, I am still reluctant for those earth worms swallowed alive (Japan or Korea ?), even if not that size lol