Mammalian Physiology

Types: Poikilothermy: body temp varies with environment Homeothermy: maintenance of constant temperature Mechanism: Ectothermy: use external sources to regulate heat (cold-blooded) Endothermy: use internal sources (warm-blooded)

Mammals are endothermic homeotherms - mammals use up to 10x as much energy as equivalent-sized mammals Mammals have fur/hair to provide insulation Mammal body temperature is generally regulated at 37±1 °C but can vary (e.g hibernations, fevers)

Maintaining body temperature requires energy - cost is minimised when environmental temperature is closest to body temp (Tb) Each species has a range of environmental temperatures at which it can maintain Tb at low cost - the Thermal Neutral Zone (TNZ) (can be fine-tuned by changing insulation) when environment goes above or below TNZ the cost of maintaining Tb increases considerably