This scratchy hiss is the closest thing yet to caterpillar vocalization
Pulling air into the gut helps sphinx hawk moth larvae make their own teakettle howl
![teakettle caterpillar](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2018/02/022618_SM_caterpillar_feat.jpg?fit=860%2C460&ssl=1)
HEAR ME ROAR Annoy this Nessus sphinx hawk moth caterpillar and it will create a hissing noise, perhaps similar to the way teakettles whistle.
J. Yack