Extinction Event at the End of the Pleistocene

The end of the last glaciation turned out to be the swan song for a substantial number of large mammals. All the proboscidians (mammoths and mastodons), the North American horses and camels, the Pleistocene large-horned bison, and giant sloths became extinct at the end of the last glaciation, along with many of the large predators. Why did this happen? The obvious answer might seem to be that these cold-adapted animals could not tolerate the warm climates of the Holocene (the current interglacial period that began 10,000 years ago). This might be convincing, if it were not for the fact that the same cold-adapted species withstood the warm climates of several previous interglacial periods, at least one of which was probably substantially warmer than anything yet experienced in the Holocene. So climatic warming per se was not enough to cause the extinction of the megafaunal mammals (animals greater than 40 kg live weight are called megafauna). There must have been some unique environmental factors influencing the megafauna at the end of the last ice age. Some argue that human beings were the most important agents in dispatching the Pleistocene megafauna. Others argue that a combination of circumstances, including both environmental change and human hunting pressure, brought about the extinction of these animals. This question is still being debated by paleontologists.

0 0

Post a comment