Tobiano is a pinto pattern caused by the T gene. It's a dominant gene; TT and Tt are tobiano, while tt is not. Tobiano can be distinguished from other pinto patterns because a tobiano horse has white that crosses its spine somewhere between the withers and the tail (topline), as if the white had been poured on from above. Tobianos also almost always have white stockings on all four legs; often the white socks blend into the white on the body. A solid-colored leg on a tobiano is almost unheard of.

The foal above is a nice, classic tobiano. He has a solid white topline, white on all four legs, and a colored patch on his flanks. He also has pretty normal-looking facial markings, such as might be found on a nonspotted horse (more on this later). He's a bay tobiano -- horses of all pinto patterns are referred to by their base color followed by their pattern type.