Idiom: Barking up the wrong tree
OED definition: Be pursuing a mistaken or misguided line of thought or course of action
Example: his wife thinks he’s having an affair, but I think she’s barking up the wrong tree
This phrase is believed to come from the use of dogs during hunts. Dogs were frequently used because of their strong sense of smell, which enabled them to track and closely follow other animals. Armed with the scent of the animal, a dog would usually give chase and persistently follow the animal until it is caught. In order to avoid this, the fleeing animal would try to escape and do so by climbing a tree, as the dog would be unable to follow them. Therefore the dog would usually stay at the base of the tree and bark upwards towards the leaves to give the hunter an indication of where the animal went. However, on occasion, the dog would get it wrong and would choose the wrong tree. In these cases the dog would literally be ‘Barking up the wrong tree’, as the fleeing animal would be safely tucked up somewhere else.
The earliest known use of this phrase is in James Kirke Paulding’s ‘Westward Ho!’ in 1832. Very soon afterwards, the expression began to be used figuratively, which can be seen in the example from ‘Knickerbocker Magazine’ from 1836, which reads:
“You’ve been barking up the wrong tree, cried the Ohioan.”