Antarctic Megafauna

Abstract

The megafauna (Greek μεγα: great; Latin fauna: animal life) of Antarctica is defined by absence. Two classes of vertebrates, reptiles and amphibians, are missing from the continent and its surrounding waters, and Antarctica has lacked true land vertebrates since dinosaurs last roamed the continent in the late Cretaceous. The ocean is the foundation of all vertebrate life in Antarctica, and none of its native birds and mammals can survive permanently in the continent's frigid, white interior. Antarctic vertebrates are all classified as marine and ultimately derive their food from the sea. Unlike in much of the Arctic, the harsher climate of Antarctica does not allow for significant plant growth, and no vertebrate herbivores exist. Antarctica's long isolation from other landmasses has resulted in the absence of surface predators such as the polar fox Alopex lagopus or polar bear Ursus maritimus, an important distinction between Antarctic and Arctic habitats. Antarctica and the Southern Ocean present some of the most challenging environmental conditions on Earth, including extreme cold, wind, dryness, radical seasonal changes in photoperiod, and extensive ice cover. But Antarctica also offers tremendous opportunity because it is a continent free of terrestrial mammalian predators, and the Southern Ocean surrounding the Antarctic continent includes some of the most productive marine habitats in the world.