ラッセル・テリア
Small tan and white terriers that technically belong to other breeds are sometimes known erroneously as "Jack Russells". Each breed has different physical characteristics according to the standards of their national breed clubs; size and proportions are often used to tell them apart. Some authorities recognize a similar but separate breed as the Russell Terrier – a shorter-legged, stockier dog, with a range of . However, the "Fédération Cynologique Internationale" (FCI) regards the Russell terrier as a sub-type of Jack Russell terrier. Jack Russells are also frequently confused with the Parson Russell Terrier. Technically, the Parson Russell is usually larger and officially limited to a middle range, with a standard size of , whereas the Jack Russell is a broader type, with a size range of