The deer that frequently dine in the field behind our house generally do so at a great distance.  Apparently, they have now determined the precise extent of Nala’s electric containment fence. She goes apoplectic when they come right up to the edge of the yard and they just keep on eating as if without a care in the world. If I did not think it would undermine her respect for the invisible fence line, I would love to take her collar off, just once, to see how that affects the deer’s calculations.