ABSTRACT Realizing suspended animation for humans would be transformative for the society: in long term applications where months of preservation is needed, it would enable planetary missions to Mars and beyond. In the more immediate uses it could be enabling for delayed resuscitation purposes in certain cases. Extended suspended animation is commonly observed in nature including several mammalian species which hibernate at subzero environments with ambient temperature as low as -30 ºC. While such high subzero temperatures (defined here as 0 ºC to -30 ºC) is utilized commonly by nature as a means to establish whole organism preservation for extended durations, subzero non-freezing preservation has not been explored for mammalians in literature (see Significance) and remain a profitable area for research. Our overarching goal is to push the boundaries of scientific discovery by enabling metabolic stasis and reanimation for an organism without the natural capacity for suspended animation. The objective of this NIGMS exploratory research grant for technology development is to test the viability of sub-zero, non-freezing (SZNF) storage of a mammal for the first time in literature. The studies would also lead to preliminary data in a context where none exists, which in turn would enable continuation with a more traditional funding mechanism once the risks are reduced and mechanistic targets are identified to enable hypothesis driven research. This objective was formulated based on our team's prior success in scaling subzero nonfreezing preservation to human livers, which provided us with key new technologies enabling control of intracellular carbohydrate levels, understanding of endothelial sensitivity to ischemia and strategies for mitigation, and machine-assisted recovery/reanimation techniques to ameliorate preservation injury. However, the transition from a single organ to an entire mammalian organism presents a vertical step forward, a potential breakthrough but with considerable risk. As such, this technology design-directed proposal specifically matches the program requirements for this exploratory grant mechanism. As a result of these studies, we expect to develop novel technologies that enables preservation of neonatal and post- natal mice in subzero temperatures. To do so, we aim to develop several novel protocols and cryopreservatives to avoid freezing in the context of whole-organism storage. These results are expected to lead to preliminary data that shows survival after days of subzero storage, which will motivate future research, as well as key data that will enable formulation of new hypotheses that will enable the utilization of more traditional funding mechanisms.