One of my geldings has trailer radar you wouldn't believe, and never seems
to forget an area we've ridden in; but my mares are no slouches either.
One thing I *have* noticed: the geldings seem to rely on visual cues and
the mares have their noses to the ground (we call the one mare "hound
horse"). If I've come crashing thru some brush to transition from one
trail to another (like down in our riverbed area), on the return trip
either of the geldings will be looking up trying to get his bearings,
whereas either of the mares will put her head down and apparently sniff the
back trail -- and the mares find the entry into the brush a lot faster.
-- Lynn K. (Santa Ynez, CA)
http://www.silcom.com/~lkinsky