Even short haired rabbits can have problems with knots or matting of their fur especially around their private parts.
When faced with knots the first point of call is to try to gently tease out the knot with your fingers. Just pull gently on little bits of the knot at a time and pull the knot apart without pulling on the skin.
When grooming or knot pulling give your rabbit a rest between sessions as they normally don't like being held for too long especially if you are knot pulling!
Think twice before using scissors on a knot or mat. Because the matted knot might be tightly knotted near the skin it is risky to cut with scissors as you stand a good chance of cutting away a chunk of flesh.
Read about long haired Angora Rabbits and learn more about caring for their long fur.
