Megafauna

Megafauna are large animals, classified by body mass or ecological role. The term often describes large species that lived during the recent geological past.

Megafaunal extinction: The disappearance of large-bodied animal species, especially during the late Pleistocene and early Holocene. The loss of many megafaunal species transformed ecosystems on several continents.
Mammoth: An extinct genus of proboscideans that included the woolly mammoth of the Pleistocene. Mammoths are among the best-known extinct megafauna.
Body mass: The mass of an organism, a measurable trait that influences its physiology and ecology. Megafauna are often defined using a body-mass threshold, though no single cutoff is universal.
Quaternary extinction event: A major loss of large animals during the late Pleistocene and early Holocene, occurring on multiple continents. It frames the broad pattern of megafaunal disappearance that competing explanations seek to explain.
Microfauna: Small animals, especially those classified by size within a particular ecological or fossil context. It names the small-bodied end of faunal classifications that megafauna contrasts with.
Trophic cascade: An ecological chain reaction in which changes at one trophic level affect multiple other levels. Removing large herbivores or predators can trigger cascading changes in vegetation and food webs.
Woolly rhinoceros: An extinct rhinoceros adapted to cold steppe environments across Eurasia during the Pleistocene. Its fossils document a large herbivore of Ice Age grasslands.
Metabolic rate: The rate at which an organism uses energy to sustain biological functions. Large body size changes energy requirements and helps determine how many individuals a habitat can support.
Overkill hypothesis: The hypothesis that human hunting drove or substantially accelerated prehistoric megafaunal extinctions. It emphasizes human predation as a cause of losses after people reached new continents.
Mesofauna: Animals of intermediate size, with the precise range depending on the field and classification system. It occupies a size category between microfauna and megafauna in some schemes.

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