Tobiano vs Overo

An addendum to Saturday's post about Ace's Black Tie Affair. Using old rules Ace would have been called an overo because his pinto white doesn't cross his back. An overo is any pinto that's not tobiano. Chincoteagues have been tested to have 5 of the over 50 non-tobiano white/pinto patterns.

Overo usually refers to frame overo. The white "frames" the body, usually has a white face and dark legs, and the white does not cross the back. We now know that tobiano sometimes doesn't cross the back so we have to throw that rule out. Here's a picture of bay minimal tobiano Rosie’s Teapot and a bay frame Paint Horse mare that was at the barn I board at. Compare them and you'll see they in general look pretty different. Rosie’s Teapot has white on all 4 legs and minimal white on her face. The Paint mare has dark front legs and an almost bald face. Rosie’s Teapot’s pinto has much smoother looking edges and is less jagged and disjointed looking than the Paint mare's.

There were two historical instances of frame in Chincoteagues. Thankfully it's far in the past and no longer present. Frame is the cause of Overo Lethal White Syndrome (OLWS) and would be a serious problem with contained feral herds. Read more here: https://www.thecolorfulchincoteague.com/framepinto.html