Possible Clues:

• Leafless succulents
• Plants' limited economic activity
• Tunas caught - feeding pet with one
• Spiny florae
• Western movie backdrops
• Tough plants show some dramatic activity
• They connect to points in the Southwest
• In historic action, they shoot in the desert
• To do in a number of Dalmatians could be prickly
• They're decidedly prickly about beginning of play