I came across these two bristle worms from the genus Nothria whilst sorting out the animals from a sample collected in the Barents sea by the MAREANO project, and wanted to show you how differently they’ve approached the choice of building materials for their tubes. They build the tube around their bodies to protect themselves from predators. Now, a Nothria outside its “house”, or tube, looks like this (scale bar is 2 mm) :

Nothria out of tube

The same animal inside its tube looked like this:

Typical tube, built out of sand grains and small rocks

And then there was this one, who had made a more select choice of building materials:

Fancy edition; built using empty bivalve shells