This category is for Extremophiles: organisms that are capable of withstanding extreme environments. Many Archaea are extremophilic. The category name is unfortunate as it calls for subjective judgements on two levels - firstly, the degree of deviation from 'normal' justifying the use of 'extreme', and secondly, whether the organism prefers the environment or merely tolerates it. A more objective approach might be the use of the suffix '-zoa' for the subcategories e.g. Halozoa, Barozoa, Xerozoa etc. and to dispense with Category:Extremophiles altogether or rename it to a more objective term.