Many prokaryotes are adapted to live inside the body because the majority of bacteria are mesophilic.
Depending on the optimal temperature of development, there are three types of bacteria:
* Mesophilic bacteria prefer average temperatures between 20 and 40 ° C. The majority of bacteria is mesophilic. This is the case of pathogenic bacteria of man and animals, but also commensal bacteria of natural cavities, cutaneo-mucous membranes and especially saprophytic environmental bacteria involved in the degradation and recycling of dead organic matter. (necromass).
* The psychrophilic bacteria have an optimal temperature of development close to 0 ° C.
* Thermophilic bacteria can live at high temperatures (45 ° C in hot springs).