The Bilgorai horse is one of the equine races that are counted among the smaller Polish horses named “mierzinky”. These horses managed to survive from the prehistoric times in the remote areas, far from railroads and distanced from the more intensive agricultures, hence they retained a relative pure form of the wild type. Prawochenski also states, that one of the reason why these horses managed to survive till this day was their small size, which saved them from the military requisitions. The pupils of professor Prawochenski, engineers Grabovsky and S. Z. Zach measured and described these horses in which the professors Vetulani and Antonius saw the remnants of domesticated ancestors of the forest tarpans, whose last herd survived in the Zamoysky region. Even the old name tarpan was preserved here for these little horses. According to Grabovsky and Zach’s measurements the average height of these horses is/was 130 to 135 cm. The heads are relatively heavy with large dark eyes, but wide and often bulged forehead and in the nose part thin; hence the tarpan type is hereby visually noticeable. The neck is short, strong, a little withers, back is straight, relatively wide and well tied in loins to the pelvis which is somewhat short and slanted; the legs are dry, the front stand often toed out and the hind often cow hocked, the hoof is strong. The typical color of the Bilgorais is yellowish gray or gray with a dark stripe the length of the back. Less often can be seen a dark brown, brown or chestnut. The power of these little horses in the pull/draft is remarkable.

The more northern type of these horses are/were bred in Lithuania known as “shmudzim”, which are somewhat taller than Bilgorais, 140 cm tall, more of muscularly rounded shapes, but in the head more refined than the Bilgorais.