What Is Megafauna?
The megafauna comprises the large or giant animals of an area, habitat, or geological period in terrestrial zoology. Megafauna simply means big animals. As are giraffes, whales, cows, deer, tigers, and even humans, the elephants are megafauna.
These are found in all the terrestrial regions of the world. The average weighting threshold for megafauna is over 40 kgs or over a tonne. However, in practice, land animals larger than a human and are not domesticated constitutes megafauna. It is used for the largest extant and extinct terrestrial wild animals. For eg., Giraffes, elephants, rhinoceros, hippopotamus, etc. In academic and popular writing, the most common usage encountered describes land mammals roughly larger than a human that are not (solely) domesticated.
Charismatic Megafauna
With the widespread popular appeal due to their attractive appearance the huge plant and animal species are known as charismatic megafauna. They can be identified easily. The giant panda, lion, humpback whale, grey wolf, bald eagle, etc. some of the charismatic megafauna in the world.
These animals are generally used by environmental activists in conservation campaigns because they can attract the public. Most of the organizations use these animals as their logos. For example the World Wildlife Fund uses Panda in their logo.
Extinct Megafauna
There are a large number of extinct megafauna. When there were no human settlements in an era the animals freely evolved. The extinction of the megafauna is being led to human interference. Early humans would have hunted these large animals to feed their families which led to the reduction in their number. Also, the large predators would have been killed to protect themselves from attack. The changing climate and atmosphere was another reason which led to their extinction over the years. There were sharks 50 feet long, wild otters as huge as wolves, and many more.
Following are the examples of some prominent megafauna that existed millions of years ago:
1. Glyptodon: These mammals became extinct 10,000 years ago. The glyptodons were the size of a VW beetle and were a well-armoured body with sharp spikes to protect themselves from predators. But they could not pull their head inside the hard turtle-like shell and depended upon their armoured body for defence.
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2. Argentavis: These were known to be the largest flying birds. It could grow to 24 feet which is twice the size of the largest bird, Andean condor, today. Their heavy body would have made it difficult to take off while flying, and so they are believed to have built their homes in the mountains. The bird was a scavenger and fed on the dead and decaying matter.
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3. Paraceratherium: It is one of the largest known mammals that have lived on the earth to date. It existed 25 million years ago and is believed to be 20 feet tall. They are believed to have fed on grass. Because of fewer fossil records available to the archaeological department, its appearance is not clear.
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4. Megalania: These were 23 feet long and weighed 4000 pounds. In Southern Australia it has lived during the Pleistocene era and is believed to be the largest venomous creature at that time. They fed on other large animals.
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Pleistocene Megafauna
These megafaunas appeared during the Pleistocene epoch. The giant birds, mammals, and reptiles in the late Pleistocene age got extinct in the Quaternary Extinction Event. Various factors such as altered habitat condition, climate change, disease, and the breakdown of food webs are considered responsible for the extinction of megafauna in this era.
The recent researches have come up with the overkill hypothesis responsible for the extinction. According to this hypothesis, human colonization was the main reason for the extinction of these animals in the Pleistocene age. Humans started hunting animals for food and to protect themselves from any harm. Slowly the animals became extinct.
Fun Facts
1. The term is most used for the Pleistocene megafauna – the large land animals of the last ice age, such as mammoths. For the largest living wild land animals, especially elephants, giraffes, hippopotamus, rhinoceros, elk, condors, etc, it’s also being used.
2. Most of the large land animals which were alive 12,000 years ago are now extinct, and there is much discussion as to what has caused this. The two main theories are hunting by humans, and climate change. These reasons together are enough to explain why these previously successful animals are now extinct.
3. Elephant birds on Madagascar were certainly hunted to extinction, as were the Moas in New Zealand. Archaeological sites With evidence of moa hunting there are archaeological sites in all over New Zealand. About five hundred years ago the moas became extinct. The moas had survived being hunted by Haast’s Eagle, but they did not survive being hunted for food by the Maoris.