Behind the front feet (specifically, behind the metacarpal/metatarsal pads) of some Labrador Retrievers are white spots or “thumbprints” called “bolo marks.” They’re named after the English Dual Champion Banchory Bolo (1915 – 1927), the first dog to earn a dual championship by winning both a bench championship as well as a Field Trial Championship in England. Some of today’s Labradors have them, and most breeder-judges are aware of the marks and ignore them (depending upon their size). As an aside, not only did many of Bolo’s pups carry the mark, but each of Bolo’s litters produced either a Field Champion or a Show Champion. Bolo had a tough start in life which you may find a compelling read.
Bolo mark on paw image found on Pinterest and happily credited upon receipt of information. Painting of Dual Ch. Banchory Bolo (1922) by Reuben Ward Binks