Biology: The evolutionary origin of body heat

The ability to control the body temperature in most mammals may have evolved as a mechanism to protect offspring and decrease juvenile death rates according to research published in Nature Communications.

The ability to maintain stable temperature probably helped mammals to exploit colder climates. Most mammals, including humans, shiver to generate heat, but an alternative source of body heat is brown fat, which generates heat in a non-shivering manner.

To understand more about the origins and evolutionary role of non-shivering heat generation, Martin Jastroch and colleagues study lesser hedgehog tenrecs, mammals from Madagascar that can only maintain a constant body temperature for short periods. The distribution of brown fat in this species suggests that non-shivering heat generation may be particularly important during periods of offspring incubation. The authors propose that this type of heat generation was selected through evolution for parental care in a first stage, and its presence subsequently facilitated species radiation to cold climates.