How do cockles primarily position themselves in sandy or muddy substrates?

Answer

They are free-living burrowers using a muscular foot.

Cockles are typically free-living burrowers that utilize a muscular foot to dig themselves just beneath the surface of the sediment, unlike species that bore or use byssus threads.

How do cockles primarily position themselves in sandy or muddy substrates?
seaanimalclassificationmolluskcockle