Animal size

thumb|320px|The African bush elephant (foreground), Earth's largest extant land animal, and the [[Masai ostrich (background), one of Earth's largest extant birds]] In zoology, megafauna (from Greek 'large' and Neo-Latin 'animal life') are large animals. The precise definition of the term varies widely, though a common threshold is approximately , this lower end being centered on humans, with other thresholds being more relative to the sizes of animals in an ecosystem, the spectrum of lower-end thresholds ranging from to , the latter largely restricted to megaherbivores. Large body size is gene

ecogeographical rule

form of phyletic dwarfism

evolutionary phenomena leading to an increase of the size of species with insularity

tendency for deep-sea species to be larger than their shallower-water relatives across a large taxonomic range

ecogeographical rule in evolutionary biology stating that members of a species get smaller or bigger depending on the resources available in the environment

A postulation pertaining to evolution

Gigantothermy (sometimes called ectothermic homeothermy or inertial homeothermy) is a phenomenon with significance in biology and paleontology, whereby large, bulky ectothermic animals are more easily able to maintain a constant, relatively high body temperature than smaller animals by virtue of their smaller surface-area-to-volume ratio. A bigger animal has proportionately less of its body close to the outside environment than a smaller animal of otherwise similar shape, and so it gains heat from, or loses heat to, the environment much more slowly.

dinosaur mass and length estimates

biological rule in allometrics, concerning the relationship between the extent of sexual size dimorphism and which sex is larger