When ‘montane’ and ‘prairie’ ticks, (Dermacentor andersoni Stiles) were liberated on the briskets and rumps of cattle stalled in a barn, the montane ticks tended to remain on or move to the upper side of the animals, and the prairie ticks on or to the lower side. The montane ticks did not move downwards and the prairie ticks did not move upwards. The literature indicates that attachment to the upper side of cattle may be prevalent in the northwest portion of the tick's distribution. No genetic incompatibilities were revealed in crosses of British Columbia and Saskatchewan ticks, and the behavior of the F1, adults appeared to be a mixture of ‘montane’ and ‘prairie’ types.