Are tardigrades the most indestructible animal on earth?

the answer to that question, of course, depends on what is intended by ‘indestructible’

tardigrades exhibit amazing resilience, arguably the most-impressive among animals

studies reporting surviving in a desiccated, ametabolic state for a century (contested) or in a frozen state for 30 years (uncontested) are remarkable

some data about tolerance to some ‘destructive’ factors are presented immediately below in point-form

·        desiccation: specimens in some species can be dehydrated, losing essentially all water, with reanimation following rehydration

·        radiation: 5000 Gy gamma radiation (the radiation type that, in the Marvel Universe, transformed David Banner into the Incredible Hulk; for reference, 1 Gy = one joule radiation energy per kilogram; 5-10 Gy kills humans)

·        temperature (low & high): -273 ØC (dehydrated) and -253 ØC (hydrated, for 35 minutes) have been reported but -180 ØC (dehydrated, 14 days) definitely is possible & 110-151 ØC (30 minutes)

·        specimens have been sent into orbit aboard spacecraft, showing tolerance to extreme conditions (vacuum, low temperature, high radiation) with extents determined by combinations (e.g., vacuum & temperature shielded from radiation, etc.) but surviving nevertheless

all these data are conditioned on the fact that only 1-2% among the 1400 species have been ‘tested’ experimentally; tolerance depends on multiple factors (including the state in which individuals are tested – e.g., hydrated or dehydrated – and usually only one extreme factor is tested in an experiment); and, of course, active individuals must eat to persist (i.e., specimens could be ‘destroyed’ through starvation)