Megafauna Extinctions

At the end of the last ice age 85 % of the large mammals (megafauna) went extinct. The mass extinctions were neither universal nor synchronous, and the reasons proffered for them include human intervention and climate change.

Many large animals (megafauna) became extinct in the past 50,000 years. They died before and after the end of the last glaciation, and some scientists have attributed their extinction to their inability to adapt to rapidly changing environments. Other scientists, however, propose that the megafauna became extinct because people killed them. Mammoths (wooly mammoths) roamed Arctic and temperate regions during the last Ice Age and were a major food source for people. Most of the mammoths died when glaciation came to an end about 15,000 years ago, and whether they died because of hunting or because of climate change is unclear.

Many other animals in North and South America died at the same time as the mammoths or slightly earlier. They include mastodons, saber tooth tigers, sloths that lived on the ground, and horses, which were reintroduced to the Americas by European colonists. Similar extinctions occurred in Australia about 25,000 years ago and New Zealand about 1,000 years ago. One of the victims in Australia was Diprotodon, which were 10 feet long and the largest marsupial that ever lived. A principal casualty in New Zealand was the Moa, a flightless bird that weighed up to 500 pounds. Extinction of megafauna in the Americas began slightly before peo­ple arrived and was completed after people crossed the Bering Strait about 13,000 years ago (see Peopling of the Americas in Chapter 1). Extinctions in Australia occurred shortly after Aborigines arrived and in New Zealand soon after Maoris arrived. The dodo, a flightless bird about 1 meter tall, was alive on the island of Mauritius when Europeans arrived in the 17th century. Shortly after their arrival, it was "dead as a dodo." This coincidence between extinction and the first arrival of people supports a proposal by Paul Martin of the University of Arizona that the death of the megafauna by over hunting was a "blitzkrieg."

Questionnaire:

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