A Precambrian rabbit is a hypothetical fossil that anti-creationist-leaning scientists have given as an example of what could change their minds. It was originally stated by J.B.S. Haldane (1892–1964) but in certain circles, especially philosophy of science, has taken on a life of its own: a frenzy of speculation and other very typical academic activities.  
This precambrian rabbit is, essentially, a metaphor for this puzzle: since there is an order in the fossil record, with primitive life forms occupying deeper (and, radiometrically, older) layers, how do Creationists explain that there are no modern lifeforms (like rabbits) in older sediments (like those from Cambrian or earlier)?
- Theory and Reality: An Introduction to the Philosophy of Science, Peter Godfrey-Smith, University of Chicago Press, 2003 ISBN 0226300633, 9780226300634, 272 pages, p. 72, 73, 74, 157, 158
- Evolution, Mark Ridley, Edition: 3, illustrated, Blackwell Publishing, 2004 ISBN 1405103450, 9781405103459 751 pages, p. 66
- Feedback: Where Are All the Bunny Fossils?, site www.answersingenesis.org