Ectotherms regulate body temperature by seeking an environment with the appropriate temperature.
Endotherms use internal metabolism to generate heat. Homeotherms maintain constant body temperature, and heterotherms have temperatures that fluctuate with their surroundings. Animals regulate their body temperatures metabolically, behaviorally, and with anatomical and physiological adaptations. Osmoregulation is the control of ion concentrations in body fluids. Specific osmoregulatory adaptations depend on habitat.