The Fox Terriers is a alert, lively, and smart. They're also prone to mischief, being charming but sly. A Fox Terrier can outwit you, yet leave you laughing at his antics. Their vigilant nature makes them excellent watchdogs, but it also means they tend to be nuisance barkers. Outgoing and inquisitive, Fox Terriers are friendly toward people but don't hesitate pick a fight with other dogs. That means they're not great candidates for the dog park.