The mole is a burrowing beast, described as blind in medieval bestiaries; it was considered the archetype of secrecy (since it labors underground). It was also called a “moldiwarp” [Franklyn 232]. The mole is a period charge, dating from c.1480 in the arms of Metford [DBA2 296]. From the examples in Guillim, 1632 , and Parker , it would seem that the mole’s default posture is tergiant fesswise, as in the illustration; for Society purposes, it’s probably best to be explicit.
Elizabeth Carpenter of Rye bears: Argent, a mole tergiant descending proper within a bordure vert.
Andrew of York bears: Barry azure and argent, a mole rampant sable.