Urchin sings too?

This is a very interesting field of research.

I have been hearing a lot of clicking and fidgeting sounds in highly-urchin infested HK waters. Little do I know that they really do come from urchins!!!

I know that not only mammals, whales, fishes, crustaceans make sounds underwater but now urchins too???

Wonder what indications do they present?

I miss being a very curious marine biologist. It is boring working with rocks... Too safe.

Photo : The Age