Abstract: A climb inhibiting structure for integration with, or attachment to, a fence run incorporating a longitudinally extending rod-like bearing member that is mounted in parallel-displaced relationship with the top extreme of the fence run. A series of relatively short turn cylinders are rotatably mounted, end-to-end, about the bearing member. A plurality of spine-like members extend radially outwardly from the surface of each rotatable member in spaced relationship precluding purchase by an animal's leg or paw. The spines are preferably yieldable so as to substantially minimize injury to climber, with rotation of the spine carrying member precluding a purchase by means of which the climber might pull itself up and over the fence.