Pleistocene megafauna
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| Subdivisions of the Quaternary period | |||
|---|---|---|---|
| System | Series | Stage | Age (Ma) |
| Quaternary | Holocene | 0–0.0117 | |
| Pleistocene | Tarantian (Upper) | 0.0117–0.126 | |
| Ionian (Middle) | 0.126–0.781 | ||
| Calabrian (Middle) | 0.781–1.806 | ||
| Gelasian (Lower) | 1.806–2.588 | ||
| Neogene | Pliocene | Piacenzian | older |
| In Europe and North America, the Holocene is subdivided into Preboreal, Boreal, Atlantic, Subboreal and Subatlantic stages of the Blytt-Sernander time scale. There are many regional subdivisions for the Upper or Late Pleistocene, usually these represent locally recognized cold (glacial) and warm (interglacial) periods. The last glacial period ends with the cold Younger Dryas substage. | |||
Pleistocene megafauna is the set of species of large animals — mammals, birds and reptiles — that lived on Earth during the Pleistocene epoch and became extinct in a Quaternary extinction event. These species appear to have died off as humans expanded out of Africa and southern Asia, the only continents that still retain a diversity of megafauna comparable to what was lost. The Americas, northern Eurasia, Australia and many larger Islands lost the vast majority of their larger and all of their largest mammals. Three theories have been given for these extinctions: hunting by the spreading humans, climatic change, and spreading disease. A combination of those explanations is also possible.
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[edit] North America
Pleistocene fauna in the Americas included giant sloths, short faced bears, California tapirs, peccaries, the American lion, giant condors, Miracinonyx ("American cheetahs", not true cheetahs), saber-toothed cats (like Smilodon and the scimitar cat, Homotherium), dire wolves, saiga, camelids such as two species of now extinct llamas and Camelops, at least two species of bison, stag-moose, the shrub-ox and Harlan's muskox, horses, mammoths and mastodons, and giant beavers as well as birds like teratorns. In contrast today the largest North American land animal is the American bison.[1]
[edit] South America
South American wildlife in the Pleistocene varied greatly, from the birds such as Phorusrhacos, to the giant ground sloth, Megatherium. The continent also had quite a few grazers and mixed feeders such as the camel-like litoptern Macrauchenia, Cuvieronius, Stegomastodon, Doedicurus, Hippidion and Toxodon. The main predator of the region was Smilodon, which crossed the land bridge between North and South America one million years ago.
[edit] Australia
Australia was characterized by marsupials, monotremes, crocodilians, testudines and monitors and numerous large flightless birds. Pleistocene Australia supported large Short-faced kangaroo (Procoptodon goliah), Diprotodon (a giant wombat), the Marsupial Lion (Thylacoleo carnifex), the flightless birds Genyornis and Dromornis, the 5-meter snake Wonambi and the giant lizard, the megalania.[2][3]
[edit] Eurasia
As with South America, some elements of Eurasian megafauna were similar to those of North America. Among the most recognizable Eurasian species are the woolly mammoth, aurochs, cave lion, cave bear, Irish elk, woolly rhinoceros and Elasmotherium. In contrast today the largest European land mammal is the European bison or Wisent.
[edit] Insular
Many islands had unique megafauna that went extinct upon the arrival of humans. These included giant bird forms in New Zealand such as the moas and Harpagornis (a giant eagle); Archaeoindris, a gorilla-sized lemur, two species of hippopotamus and the gigantic Aepyornis in Madagascar; dwarf Stegodon on Flores and a number of other islands; dwarf woolly mammoths on Wrangel Island and St. Paul Island; land turtles and crocodiles in New Caledonia; giant owls and dwarf ground sloths in the Caribbean;[4] giant geese and moa-nalo (giant ducks) in Hawaii; and dwarf elephants and dwarf hippos from the Mediterranean islands.[5]
[edit] References
