On the Track of Unknown Animals is a cryptozoological book by the Belgian-French author Bernard Heuvelmans that was first published in 1955 under the title Sur la Piste des Bêtes Ignorées. The English translation by Richard Garnett was published in 1958 with some updating by the author and with a foreword by Gerald Durrell. A revised and abridged edition was published in 1965, and a further edition in 1995.