Distribution in scandinavian waters
Maximum length: 3 cm.
Appearance: Rock lice have a distinctly segmented back. The antennae
are long, while the extremeties of which are highly jointed. The last
pair of legs on the hind, point backwards, are branched and nearly of
the same length. Rock lice are the largest of the related specie. They
are mainly dark brown to black in colour, but can
change colour like many other crustaceans.
Depth: From the water-line and about 10 m up on land where the
Environment: Lives on cliffs
and rocky beaches. Occasionally venturing into the water.
Misc: Rock lice are rather timid. Most individuals are out rumaging
at night. They disappear very quickly into crevices or the water when
attempts are made to catch them.
Mainly fall prey to shore crabs and birds.
Feed mostly on seaweed.
They can be as old as 3 years, and it is at this age they
mate. The young do not live as larvae in the sea, but leave
their mother fully developed.
Classification: Rock lice are isopods, which are crustaceans
under the arthropods.
There are many different specie of louse that
live in the sea, but rock lice are the closest relatives to
the land-living woodlice.