The invention provides an animal training aid or toy for use in scent based animal training or activities. The aid or toy comprises: a housing comprising an interior cavity configured to contain a scented material that releases substantially no scent that is desirable to the animal in an unactivated state and releases a scent that is desirable to the animal in an activated state； one or more vents on an external surface of the housing, each vent in communication with the interior cavity so that a scent from the scented material can be released from the interior cavity to the exterior of the housing where it can be detected by the animal； and an activator for activating the scented material from the unactivated state to the activated state, the activator being operable from the external surface of the housing.
