Smithsonian magazine interviews Charles Lefevre who is fanatical about truffles, mushrooms that sell for anywhere from $100 to $1500 a pound depending on the variety. Lefevre "hunts" truffles in Oregon and also sells trees inoculated with European truffles so farmers in the US can start their own truffle orchards. From the interview:
Why don't hunters here use pigs and dogs like they do in Europe?Link
Most of the hunting is done surreptitiously at night without [a landowner's] permission. If you're driving around with a pig, everyone knows what you're doing.
I've been hunting with dogs, and they're preferable. Any dog can find truffles, but dogs that love to work are best. Labs and poodles make great truffle dogs...
What's it take to be a good truffle hunter?
The principal personality trait required is the ability not to brag about it, because someone will follow you to your patch the next time you go.