Earlier people do not proclaim extinction of large mammals in Africa several million years ago, explained a new study. Tyler…
Earlier people do not proclaim extinction of large mammals in Africa several million years ago, explained a new study.
Tyler Faith, archaeologist at the Natural History Museum in Utah and his team disputes long-standing belief that early humans contributed to killing megaherbivors by hunting. Instead, the changes in the environment actually caused these animals to die out.
There were a large number of megaherbivors – planting animals weighing about 2,000 pounds – in Africa. Right now there are only five of them, namely hippo, giraffe, elephant, white rhinoceros and black rhinoceros.
Some researchers have always attributed the disappearance of these animals to the development of tool-bearing and carnivorous hominids. Apparently this is not the case.
The study published in the journal Science saw 7 million years of eradication of herbivores in East Africa. The researchers found that about 4.6 million years ago there had been a steady decline in megaherbivore diversity on the continent and it had begun long before human ancestors began to be slaughtered with animals. In fact, the decline began to weigh before the appearance of some hominins that could chase the big mammals.
The research team also looked at independent records of environmental and climate trends from the last 7 million years, especially the global atmospheric CO2 and stable carbon isotope registers of vegetation structures.
The analysis showed that 28 lines of megaherbivors were eradicated. This coincided with the expansion of grasslands that caused a decline in atmospheric carbon dioxide over the last 5 million years.
“Low carbon levels favor tropical grass over trees, and as a result, savannas became less woody and more open through time,” explained John Rowan, a researcher from the University of Massachusetts Amherst. “We know that many of the extinct megaherbivors are fed on woody vegetation, so they seem to disappear along with their food source.”
In addition, the loss of megaherbivores millions of years ago can also cause extinction of other animals. African carnivores who enjoy eating the flesh of young elephants, for example, may have died because of their primary change.