Possible Clues:

• Kudu, for one
• A swift-running animal like gazelle
• Oryx or gerenuk
• Seen before run as a very fast mover
• "... where the deer and the ___ play"
• Open late to make a quick buck
• The animal, stake to a pole, foolishly
• Deer playmate?
• Graceful deer as a lone pet
• It might sound as if 15 across would run off with one buck (8)