Such sausage-shaped piles of sand have surely been seen by every diver on the sea bottom without knowing what it is exactly.

It is the excrement of an animal, namely that of acorn worms (class: Enteropneusta). They live, invisible to us divers, 20cm to 2m deep in the sandy seabed. 

It's worth taking a closer look at this sausage-like pile of sand. You can see that the sand is slowly pushed out from the middle at the top, like when a butcher produces sausage.

There are over 70 species with body lengths ranging from a few centimeters to 2.5 m. The acorn worms themselves are characterized by a worm-like body. This consists of an elongated abdomen, a collar region and a

acorn-shaped front part, which serves as a muscular drill in the ground and helped them to get their German name. Behind the collar are gill pores, an external sign of the gill intestine developed in them.

Photos: Johann Vifian

Sources with photos: Bavarian State Collection / bspg.snsb.de/oktober-2014-eichelwurm, Université de Montreal mapageweb.umontreal.ca/cameroc/Images.htm, Wikipedia