AKC Scentwork
The sport of Scent Work is based on the work of professional detection dogs (such as drug dogs), employed by humans to detect a wide variety of scents and substances. In AKC Scent Work, dogs search for cotton swabs saturated with the essential oils of Birch, Anise, Clove, and Cypress. The cotton swabs are hidden out of sight in a pre-determined search area, and the dog has to find them. Teamwork is necessary: when the dog finds the scent, he has to communicate the find to the handler, who calls it out to the judge.
https://www.akc.org/sports/akc-scent-work/