Body temp too low: metabolism slows, bodily functions disrupted. Body temp too high: enzyme function destroyed, proteins denature. Between 0 c and 37 c for most animals. Animals use behavioural and/or physiological mechanisms to maintain body temperature independent of ambient temperature. Body temperature is kept in a range that is optimal for physiological functions, but this comes at a metabolic cost. Fainting, vomiting, severe headache, dizziness, confusion, hallucinations, delirium and drowsiness can occur. Hallucinations, delirium, complete confusion, extreme sleepiness that is progressively becoming comatose. Rate influenced by body mass, activity, digestion. An increase in body temperature increases metabolic rate. Specific dynamic effect= increase in metabolic rate during digestion results from energetic costs- mechanical processing of food (e. g. mastication and gut motility) Protein synthesis in the body protein pool and. Nitrogen excretion increase in the concentration of metabolic substrates -drive associated chemical reactions towards equilibrium= increase metabolic rate.