ABSTRACT
Winter survival for hundreds of species of organisms depends on freeze tolerance, the ability to endure the conversion of a high percentage of total body water into extracellular ice. Freeze tolerance has arisen many times in phylogeny. Among animals, examples of natural freeze tolerance can be found in most invertebrate groups, with most research into the mechanisms of freeze tolerance having been done on insects and intertidal marine molluscs. A number of species of amphibians and reptiles that hibernate on land are also freeze tolerant. Studies of vertebrate freeze tolerance
are not only fascinating examples of complex adaptations but, by identifying the organ-specific molecular mechanisms that support natural freezing, also provide insights into the issues that need to be addressed in the development of organ cryopreservation technology as an aid to transplant medicine.
