Varmblandad

Varmblandad is a term sometimes encountered in Swedish-language biology referring to warm-blooded animals, i.e., organisms that maintain a relatively constant body temperature through internal heat production. In formal Swedish scientific usage the standard adjective is varmblodig (warm-blooded); varmblandad is frequently regarded as a colloquial or less common variant and may be considered a misspelling in strict texts.

Biological meaning and characteristics

Warm-blooded animals are primarily endotherms, meaning their metabolism generates heat that sustains body temperature largely independent of ambient conditions. This group includes two major evolutionary lineages: birds and mammals. Endothermy is often accompanied by relatively high and stable body temperatures, high metabolic rates, and adaptations for heat retention and production, such as fur, fat, and, in birds, feathers.

Taxonomy and examples

Varmblandad, as a descriptor for warm-blooded, covers all mammals and birds. It excludes most reptiles, amphibians, and fish, which are typically ectothermic (their body temperature follows the environment). Within mammals, marsupials and placental mammals share endothermy, while some species exhibit regional variations in temperature regulation. Birds maintain high body temperatures through efficient respiratory and circulatory systems and high metabolic demands of flight.

Physiology and evolution

Endothermy involves mechanisms such as increased basal metabolic rate, insulation, and sometimes brown adipose tissue in early infancy or specific taxa. The evolution of endothermy occurred independently in the mammalian lineage and in the saurischian-bird lineage, with significant consequences for activity, geographic distribution, and ecological niches.

See also

Endotherm, Ectotherm, Warm-blooded.