Dunno, but I've never had a bit of trouble with them :~)
There's ripe tomatos out there for the taking too.
For that matter, there's a tree full of apples in the back forty that are rotting. I can't get varmints in my crops if I try :~D
You need some cows! We rented a house on 3 acres in Indiana, and it came with an apple orchard. The owner told us that one day he looked out and a neighbor's cows were browsing the trees in his orchard!
We did have cows come through one night, though. They escaped from the dairy farm down the road, and just kept walking across folks' back yards. I had to call the farmer about midnight to come get them.