 As west-bound shipping from Europe usually reached the subtropics at about the time the "dead horse" was worked off, the latitude became associated with the ceremony.An alternative theory, of sufficient popularity to serve as an example of folk etymology, is that the term horse latitudes originates from when the Spanish transported horses by ship to their colonies in the West Indies and Americas.Ships often became becalmed in mid-ocean in this latitude, thus severely prolonging the voyage; the resulting water shortages made it impossible for the crew to keep the horses alive, and they would throw the dead or dying animals overboard.