It was believed a long time that the Rex rabbit had only undercoats; but, in fact, all the kinds of hairs at Rex are reached of "nanism": what leads to a reduction length and diameter of these hairs. The hairs of cover thus seem to merge with the undercoats. The length of the hairs must lie between 16 and 20 mm: what gives to the animal a "velvety" aspect or a "peeling of mole".