Megafauna

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