Lumbricus terrestris is a large reddish worm native to
Europe, but now also widely distributed elsewhere around the world
(along with several other lumbricids), due to human
introductions. In some areas where it has been introduced, some
people consider it to be a serious pest species, since it is
out-competing locally native worms.
Through much of Europe it is the largest naturally occurring
species of earthworm, typically reaching 20 - 25 cm in length when
extended (though in parts of southern Europe there are native
species which are much larger). It has an unusual habit of
copulating on the surface at night, which makes it more visible
than most other earthworms.