Millions of years ago, giant herbivores roamed the Earth. The massive creatures, which were the ancestors of animals like rhinos, elephants or hippos, reached an apex moment in Africa, more than 4.5 million years ago, during the Pleistocene. Their number began to decline approximately 2.6 million years ago, a negative trend which continued until 11,000 years ago.
Previous studies suggested that the climate change and the spread of ancient humans, the precursors of humankind, may have been responsible for the extinctions. A recent paper argues that the prime cause was the change of the environment, which negatively affected the species.
This claim is disputed by another paper, which notes that our early ancestors may have contributed to recent megaherbivore extinctions, just like they are doing today.
Ancient humans might have caused the extinction of giant herbivores
The most iconic hominids genus is the Australopithecus. The first individuals appeared 4.2 million years ago and shared the land and food with a large number of herbivores. While the Australopithecus were omnivorous, it is unlikely that they hunted megaherbivores, which played an essential role in the ecosystem.
Centuries of sustained grazing and migration led to the creation of a mixture of woodland and grassland which favored the early humans. They lived in harmony with other species, at least for a while.
The situation changed as the climate was heading towards a different phase. The oceans started to cool as the amount of carbon dioxide started to decrease. The grasslands began to grow exponentially in Easter Africa, as the woodlands started to diminish and a large number of wildfires appeared.
The Australopithecus were able to adapt to the evolving conditions, but the megaherbivores suffered as the wooded areas were destroyed. According to the study, the number of megaherbivores continued to decline as early humans thrived. The use of fire and other tools may have played an essential role in the extinction, but further research is need before definite conclusions can be offered.
Brad is a former Senior Fellow at the Schuster Institute for Investigative Journalism at Brandeis University, is an award-winning travel, culture, and parenting writer. His writing has appeared in many of the Canada’s most respected and credible publications, including the Toronto Star, CBC News and on the cover of Smithsonian Magazine. A meticulous researcher who’s not afraid to be controversial, he is nationally known as a journalist who opens people’s eyes to the realities behind accepted practices in the care of children. Brad is a contributing journalist to Advocator.ca