megafaunal

Megafaunal is an adjective used to describe megafauna, large animals whose size sets them apart from smaller species. In paleobiology and ecology, megafauna typically refers to animals weighing roughly 44 kilograms (100 pounds) or more, though definitions vary and some sources use higher thresholds. The term encompasses terrestrial, marine, and avian species, both ancient and modern.

Modern megafauna include elephants, rhinoceroses, hippopotamuses, giraffes, and the large whales. Prehistoric megafauna includes woolly mammoths, mastodons, saber-toothed cats, giant ground sloths, and other large Pleistocene animals. Large body size influences physiology, life history, and ecology: megafauna generally have slow growth, long lifespans, and low reproductive rates, requiring substantial and stable resources. Their activities can shape habitats, for example through grazing, seed dispersal, and nutrient cycling, while their vulnerability to habitat loss and climate fluctuations makes them particularly susceptible to environmental change.

Geographic and evolutionary contexts produce varied patterns, including insular dwarfism on some islands and, less commonly, island gigantism in others. The end of the last Ice Age saw widespread megafaunal extinctions across many continents and islands, likely due to climate shifts and expanding human activity, with numerous lineages disappearing while others survived into the present day. Today, many extant megafauna face threats from habitat destruction, fragmentation, hunting, and climate change. Conservation efforts emphasize habitat protection, anti-poaching, and connectivity to maintain large, long-lived populations that play key ecological roles.