Megafauna

Megafauna are large animals of any particular region or time. Generally, they are defined as animals that weigh over 500 kg to 1 tonne, i.e., any animal larger than the largest widespread domestic animal, the domestic bull. Some authors use much lower thresholds, even as low as 50 kg (making humans a megafauna species), but they are not widely accepted. 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 geologically recent times.

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. 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.

Usage

The sense in which the term is used is usually apparent from the context:

1. A particular group of large, extinct animals. For example, American megafauna, meaning "the various species of large American mammal that became extinct about 13,000 years ago".
2. Any group of large animals. For example, South American megafauna, meaning "all large animals in South America today".

Extinction

Two major hypotheses have been proposed to explain the extinction of megafauna. The first cites human intervention, noting that the time of human appearances on the various continents was the time that they became extinct.

The second is that climate changes, most notably increases in average temperature, caused them to die out. However the fact that the woolly mammoth survived on at least two islands in the region of the Bering strait for thousands of years after the end of the last glaciation 12,000 years ago, indicates that climate changes was probably not the cause of their extinction.

Charismatic megafauna

The term charismatic megafauna refers to animals that have widespread popular appeal. Examples include the Giant Panda, the Asian Elephant, and the Blue Whale.

Charismatic megafauna often garner a disproportionate level of public concern. Environmental activists are aware of this effect and use the extra leverage provided by a charismatic species to achieve more subtle and far-reaching goals. By directing public attention to the plight of the Giant Panda, for example, the environmental movement can raise support not just for the protection of the panda, but for the entire ecosystem on which it depends. The Giant Panda is portrayed in the logo of the World Wildlife Fund.

Megafauna by continent

"†" denotes extinct megafauna

African megafauna

• African Buffalo
• Giant Long-horned Buffalo † (Bubalus antiquus)
• African Bush Elephant
• African Forest Elephant
• Hippopotamus
• Black Rhinoceros
• White Rhinoceros
• Giraffe
• Ostrich
• Deinotherium †
• Dinofelis †

Eurasian megafauna

• Aurochs †
• Andrewsarchus †
• Cave Bear †
• Cave lion †
• Deinotherium †
• Dinofelis †
• Entelodont †
• Giant Unicorn †
• Asian Elephant
• Indricotherium †
• Irish Elk † (or Irish giant deer)
• Mammoth †
• Komodo Dragon†
• Indian Rhinoceros
• Javan Rhinoceros
• Sumatran Rhinoceros
• Woolly Rhinoceros †
• Stegodon †
• Wisent

Australian megafauna

• Saltwater Crocodile
• Diprotodonts †
• Megalania prisca †
• Marsupial lion †

See also: Australian megafauna

North American megafauna

• Ice Age Camel † (Camelops herternus)
• Alaskan Moose (Alces alces gigas)
• American Lion † (Panthera leo atrox)
• American Bison (Bison bison)
• Ancient Bison † (Bison antiquus)
• American Mammoth † (Mammuthus columbi)
• Equus scotti †
• Giant Beaver † (Castoroides ohioensis)
• Giant Sloth † (Eremotherium rusconii)
• Mastodon †
• Megatherium †
• Saber-toothed cat † (Smilodon fatalis)
• Short-faced Bear † (Arctodus simus)
• Smilodon †
• Dinofelis †
• Teratorn † (Teratornis merriami)
• Polar Bear

Central & South American megafauna

• Glyptodon †
• Megatherium †
• Palaeolama mirifica † (an extinct Llama)
• Litoptern †
• Giant Anteater
• Giant Armadillo
• Tapius veroensis † (an extinct Tapir)

Island megafauna

• Madagascar Elephant bird †
• Moa †
• Moa-nalo †

Ocean megafauna

• Most whales
• Walrus
• Elephant Seal
• Steller's Sea Cow †
• Dugong
• Manatee
• Bluefin Tuna
• Marlin
• Basking Shark
• Whale Shark
• Giant Squid

Arctic megafauna

• Walrus
• Polar Bear
• Musk Ox
• Elephant Seal

See also

• Fauna
• Giant animals
• Bergmann's Rule
• List of megafauna recently discovered

External links

• First Victims of the Human-Caused Extinction