Megafauna

Megafauna are species of large animals (Greek μεγας, large, + modern Latin fauna, animal).

Definitions of what constitutes 'large' vary, with some authors using a 40 kg minimum,Defense of the Earth. [http://www.ukzn.ac.za/Biology/Uploads/69cd30f3-52c3-4f28-8c2c-3a99d006ab84/biol104lect6.pdf "Past consequences of climate change: Evolutionary history of the mammals".] ] others 44 kg,Stuart, A. J. (1991). Mammalian extinctions in the Late Pleistocene of northern Eurasia and North America. "Biol. Rev". 66: 453–562.] Anon. [http://www.amqua.org/publications/quaternarytimes/v29n1/quaternary_paleobiology_update.htm Quaternary Paleobiology Update] . "The Quaternary Times" 29 (1): (1999).] 45 kg,Corlett, R. T. (2006). [http://www.atbio.org/tn_v17_n3_Sept_2006.pdf Megafaunal extinctions in tropical Asia] . "Tropinet" 17 (3): 1–3.] 100 kg,Martin, P. S. & Steadman, D. W. (1999). Prehistoric extinctions on islands and continents. In: "Extinctions in near time: causes, contexts and consequences" (MacPhee, R. D. E., ed.), pp. 17–56. New York: Kluwer/Plenum.] or 250 kg.Choquenot, D., & Bowman, D. M. J. S. (1998). Marsupial Megafauna, Aborigines and the Overkill Hypothesis: Application of Predator-Prey Models to the Question of Pleistocene Extinction in Australia. "Global Ecology and Biogeography Letters" 7 (3): 167-180.] In the last case, they may be further subdivided into small (250–500 kg), medium (500–1,000 kg) and large (over 1,000 kg) megafauna. Others say that any particular limit is arbitrary, and do not favour a single minimum weight.Wroe, S., Field, J., Fullagar, R., & Jermiin, L. S. (2004). [http://www.bio.usyd.edu.au/staff/swroe/Wroeetal2004MegafaunalextinctionintheLateQuaternary1.pdf Megafaunal extinction in the late Quaternary and the global overkill hypothesis] . "Alcheringa" 28: 291-331.]

The term is also used to refer to particular groups of large animals, both to extant species and, more often, those that have become extinct in the geologically recent Quaternary period.

Megafauna animals are generally K-strategists, with great longevity, slow population growth rates, low death rates, and few or no natural predators capable of killing adults. These characteristics make megafauna highly vulnerable to human exploitation. Some authors have argued that this reproductive capacity and ecological behaviour are more important than size alone, with some much smaller animals with very low reproductive rates showing 'megafauna' characteristics, such as all Tachyglossidae (echidnas) and Megatherioidea (two-toed sloths) above 7 kg and 6 kg respectively, becoming extinct in late Quaternary megafaunal extinctions.Johnson, C. N. (2002). [http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1691151&blobtype=pdf Determinants of loss of mammal species during the Late Quaternary 'megafauna' extinctions: life history and ecology, but not body size] . "Proc. Biol. Sci". 269 (1506): 2221–2227.]

Recent extinctions

Many species of megafauna have become extinct within the last million years, and, although some biologists dispute it, human hunting is often cited as the cause.Diamond, J. (1997). "Guns, Germs and Steel". Vintage ISBN 0-09-930278-0.] Other theories for the cause of the extinctions are climatic change associated with glaciation and the questionable hyperdisease hypothesis.Grayson, D. K., & Meltzer, D. J. (2003). [http://www.unl.edu/rhames/courses/current/requiem-overkill.pdf A requiem for North American overkill] . "Journal of Archaeological Science" 30: 585–593.]

Examples of megafauna

Domestic megafauna

*Alpaca ("Vicugna pacos")
*Asian Elephant ("Elephas maximus")
*Caribou ("Ranfiger tarandus")
*Chital ("Axis axis")
*Domestic buffalo ("Bubalus bubalis")
*Domestic Dog ("Canis familaris")
*Domestic Goat ("Capra aegagrus hircus")
*Donkey ("Equus asinus")
*Dromedary Camel ("Camelus dromedarius")
*Guanaco ("Lama guanicoe")
*Cattle ("Bos taurus")
*Horse ("Equus domesticus")
*Pig ("Sus scrofa")
*Llama ("Lama glama")
*Sheep ("Ovis aries")Fact|date=October 2008
*Turkey ("Melagris gallopavo")
*Vicuña ("Vicugna vicugna")

Freshwater megafauna

*Chinook Salmon ("Oncohynchus tshawtscha")
*Giant Barb ("Catlocarpio siamensis")
*Wels Catfish ("Silurus glanis")
*Prionosuchus †

Oceanian megafauna

*Antilopine Kangaroo ("Marcopus antilopinus")
*Australian Pelican ("Pelecanus conspicillatus")
*Blue Whale ("Balaenoptera musculus")
*Bryde's Whale ("Balaenoptera brydei")
*Bluff Down Crocodile † (Quinkana)
*Bluff Down Euryzygoma † ("Euryzygoma dunese")
*Bluff Down Giant Python †
*Brolga ("Grus rubicunda")
*Bush Moa† ("Anomalopteryx didifromis")
*Carnivorous Kangaroo † ("Propleopus oscillans")
*Carpet Python ("Morelia spilota")
*Cassowary ("Casuarius casuarius")
*Congruus †
*Dingo ("Canis dingo")
*Diprotodon †
*Eastern Grey Kangaroo ("Marcopus gigantea")
*Emu ("Dromaius novaehollandiae")
*Eurapteryx†
*Fin Whale ("Balaenoptera physalus")
*Genyornis † ("Genyorns newtoni")
*Giant Echidna † ("Zaglossus hacketii)"
*Browsing Kangaroo † ("Simosthenurus occidentalis")
*Giant Maleefowl † ("Leipoa gallinacea")
*Giant Platypus † ("Ornithorhynchus maximus")
*Giant Koala † ("Phascolarctos stroni")
*Great Tasmanian Devil † ("Sarcophilus laniarius")
*Giant Wallaby † ("Protemnodon otibandus")
*Goanna ("Varanus giganteus")
*Gould's Monitor ("Varanus gouldi")
*Humpback Whale ("Megaptera novaeangliae ")
*King Island Emu † ("Dromaius ater")
*Killer Whale ("Orcinus orca")
*"Megalania prisca" †
*Marsupial Lion † (genus "Thylacoleo")
*Moa †
*Minke Whale ("Balaeonptera acutorostrata")
*New Zealand Eagle † ("Harpagornis moorei")
*New Zealand Giant Penguin † ("Pachydyptes ponderosus")
*New Zealand white shark † ("Carcharodon angustidens")
*Ninjemys oweni †
*Pacyhornis †
*Palorchestes †
*Procoptodon †
*Red Kangaroo ("Marcopus rufus")
*Saltwater Crocodile ("Crocodylus porosus")
*Sei Whale ("Balaenoptera borealis")
*Stirton's Thunder Bird † ("Dromornis stirtoni")
*Tasmanian Tiger † ("Thylacinus cynocephalus")
*Taniwhasaurus †
*Warrendja †
*Wonambi †
*Zygomaturus †

ee also

*Bergmann's Rule
*Cope's rule
*Deep-sea gigantism
*Fauna
*Island gigantism
*Largest organisms
*List of megafauna recently discovered
*List of African megafauna
*List of Arctic megafauna
*List of Australian megafauna
*List of Central and South American megafauna
*List of Eurasian megafauna
*List of island megafauna
*List of marine megafauna
*List of North American megafauna
*New World Pleistocene extinctions

References