Thanx Karen! . Also here is the breed standard for a hooded rat......
(In old books on Rats this variety is often known as Japanese Hooded) The hood shall be unbroken, covering the head, throat, chest and shoulders, except in the case of light coloured hooded varieties where a pale coloured throat is permissible. The hood shall be continuous with the saddle, extending down the spine to the tail with as much of the tail as possible being coloured. The saddle width shall be one quarter to half an inch it must be as even as possible and unbroken. The edges of the hood and saddle shall be clear cut and devoid of brindling. The white area shall be pure and devoid of yellowish tinge or staining.