Ear mites are tiny eight-legges animals that live down in the ear canal
and feed on ear wax.
The irritation that they cause stimulates the ear to produce a lot more
dark wax, and usually results in the cat doing a lot of ear scratching and
head shaking.
Drops can be put into the ear to kill off the mites and soften the wax,
but any course of treatment must be continued for at least three weeks to
kill off any eggs that may be present, and all dogs and cats in the household
must be treated to prevent cross-infection.