Super-sized Ice Age Animals Killed by Climate Change

A new study has compared the diet of a variety of Australian megafaunal herbivores from the period when they were widespread (350,000–570,000 years ago) to a period when they were in decline (30,000–40,000 years ago) by studying their fossil teeth. The analysis suggests that climate change had a significant impact on their diets and may well have been a primary factor in their extinction.

During the last Ice Age, Australia, Tasmania, and New Guinea formed a single landmass, called Sahul. It was a strange and often hostile place populated by a bizarre cast of giant animals. There were 500-pound kangaroos, marsupial tapirs the size of horses, and wombat-like creatures the size of hippos. There were flightless birds that weighed twice as much as modern emu, 33-foot snakes, 20-foot crocodiles, 8-foot turtles with horned heads and spiked tails, and giant monitor lizards that measured greater than 6 ft from tip to tail and were likely venomous. By about 30,000 years ago, however, most of these ‘megafauna’ had disappeared from the Sahul as part of a global mass extinction that saw the end of nearly all of super-sized animals that had evolved to survive in extreme Ice Age climates. The factors that forced the Australian megafauna into extinction remain a matter of considerable controversy. Many experts argue that the ancestors of the Australian aborigines, who made an appearance approximately 50,000 years ago, either hunted them into extinction or gradually destroyed the habitat they required by practices such as fire-stick burning. Others argue that the gradual drying out of Australia and weakening of the Australian monsoon played a major role in their demise.