why does my dog have a lot of black ear wax?

All dogs have some wax in their ear canals...it's normal.  However, the wax should not be black in color.  Your dog probably has contracted an infection of some type.  Ear mites and yeast infections usually are associated with a dark wax.  The waxy buildup tends to also have a distinctive odor.

You should have your dog's ears examined by your veterinarian before you clean the ears.  A close inspection of the wax and ear canals should help in making a diagnosis.

Helpful Buckeye