Shrimp Juvenile

Juveniles from sea were collected and kept in all glass tank, latter
on in a plastic box we brought two types of sand ,dividing the box
with two type of sand ne very fine & other crumbles like ,then
gently kept few juveniles on the top of sand ,immediately they started
blowing sand upwardly and slowly going downwards in sand within less
then a minute only eyes were visible, then that too disappeared
,latter on say after 20 minutes just to check we started slowly
searching in sand with our fingers and relies they were comfortable
down two cms.

Then we kept little sand on the glass base to observe they are mostly
on sand blowing it ( trying to cover them selves, maybe)

Now just for curiosity I ask few questions: what type of food could be
available between sand particles? What stimulates them to act like
this?

If some one wishes to suggest some experiments we can try it with this
little number of juveniles.


ManyThanks,
Indulkar Shailendra
India( presently in Egypt)