"Precambrian rabbits" or "fossil rabbits in the Precambrian" are reported to have been among responses given by the biologist J. B. S. Haldane when asked what evidence could destroy his confidence in the theory of evolution and the field of study. The answers became popular imagery in debates about evolution and the scientific field of evolutionary biology in the 1990s. Many of Haldane's statements about his scientific research were popularized in his lifetime.