In 1985 Krause and a colleague, Diana Reiss, helped lure Humphrey the Whale, a migrating female humpback that had wandered into Sacramento River Delta and apparently got lost, back to the Pacific Ocean. As scientific co-directors of the operation, they used recordings of humpbacks feeding, recorded by two graduate students from the University of Hawaii, recordings that Krause modified to eliminate extraneous noise and add different characteristics to the audio tracks so that the whale would not habituate to the one audio short example that was provided by the students' graduate professor.