What Is Shivering Thermogenesis?

Definition

• Derived from the Greek words "therme" (heat) and "genesis" (origin), thermogenesis means the production of heat. Shivering thermogenesis is, therefore, the creation of heat caused by shivering.

Purpose

• Shivering thermogenesis is used to heat the body when it becomes too cold. Shivering is usually triggered by exposure to cold environmental temperatures, but the "temperature set point" that triggers shivering varies among species and individuals.

Mammal and Birds

• Although all mammals and birds can shiver to produce heat, shivering thermogenesis is generally considered an inefficient method to maintain a constant, warm body temperature. Therefore, mammals and birds rely on shivering only as a last resort, when air or water temperatures are too low to rely solely on other pathways of metabolic heat production.

Reptiles

• Females of several species of large-bodied pythons use shivering thermogenesis to heat their eggs during brooding. After laying eggs, a female gathers her eggs and curls tightly around them, insulating them from environmental temperatures. She then shivers using coordinated muscle contractions to heat her eggs above background environmental temperatures, when temperatures are below her preferred set point.

Non-shivering Thermogenesis

• Non-shivering thermogenesis is the production of metabolic heat without shivering, and is caused by diet and muscle activity during movement. Non-shivering thermogenesis is the primary pathway for heat production in mammals and birds, and is more efficient than shivering thermogenesis. Shivering is only used as a last resort, once an individual has exhausted the ability to generate metabolic heat. Non-shivering thermogenesis is used less in reptiles and only contributes substantially to body heat in the largest reptile species, such as Leatherback Sea Turtles.