'Megafauna' Mystery: Ancient Humans May Have Driven Prehistoric Giants to Extinction, Scientists Claim

Scientists have long wondered about the gradual extinction of "megafauna," or the prehistoric giants that came to share the Earth with ancient humans.

Knewz.com has learned that the latest theory suggests that being hunted by humans was one of the factors why ancient giants like the woolly mammoth died out.

The study, carried out by an international group of researchers led by scientists from the Danish National Research Foundation’s Center for Ecological Dynamics in a Novel Biosphere (ECONOVO) at Aarhus University, has observed a relation between extinction patterns of megafauna and the human population of specific regions.

"The large and very selective loss of megafauna over the last 50,000 years is unique over the past 66 million years. Previous periods of climate change did not lead to large, selective extinctions, which argues against a major role for climate in the megafauna extinctions," Professor Jens-Christian Svenning, lead author of the study, said in a statement via Study Finds .

"Another significant pattern that argues against a role for climate is that the recent megafauna extinctions hit just as hard in climatically stable areas as in unstable areas."

The study noted that ancient megafauna species began gradually vanishing shortly after the introduction of humans to new regions, and found that extinction rates were always higher with the arrival of humans.

"There is strong and increasing support for human pressures as the key driver of these extinctions, with emerging evidence for an initial onset linked to pre-sapiens hominins prior to the Late Pleistocene," the research, published in the journal Cambridge Prisms: Extinction , mentioned.

"The late-Quaternary megafauna extinctions thereby represent an early, large-scale human-driven environmental transformation, constituting a progenitor of the Anthropocene, where humans are now a major player in planetary functioning."

Study Finds pointed out that megaherbivores, the class of plant -eating animals weighing over a ton, were hit the hardest by mass extinction. While there were 57 species of megaherbivores roaming the Earth 50,000 years ago, only 11 remain today, and they continue to face the threat of extreme population decline .

The research noted this as well, saying:

"Earth’s remaining megafauna are in quite a dire state, with ~47% of all living mammals weighing ≥10 kg [22 pounds] listed as vulnerable, endangered or critically endangered by the International Union for the Conservation of Nature (IUCN), and an additional ~12% listed as near-threatened."

Svenning further pointed out in his statement, "Early modern humans were effective hunters of even the largest animal species and clearly had the ability to reduce the populations of large animals."

"These large animals were and are particularly vulnerable to overexploitation because they have long gestation periods, produce very few offspring at a time, and take many years to reach sexual maturity."

The research also noticed, however, that the rate of extinction of megafauna was lower in regions where humans shared a longer evolutionary history with these prehistoric giants. For instance, Africa and Southern Asia saw "lower severity and longer time frame of the extinctions."

This could suggest that the evolving megafauna in Asia and Africa developed a pattern of behavior avoiding humans.

The research also pointed out what the disappearance of megafauna meant for the subsequent ecosystems, and the lasting environmental effects of their extinction.

Large herbivores like mammoths and ground sloths were crucial in maintaining "maintaining open habitats and dispersing nutrients across landscapes," per Study Finds , and their extinction likely contributed to the unchecked growth of forests leading to a disruption of fire patterns.

"In the terrestrial realm, there are many examples of large animals that, by engineering their environment, generate habitats or unlock resources for other species. The digging of water wells, for example, is ubiquitous among elephants and equids," the team wrote in the research.

"Other physical engineering actions that are common among ungulates and other large herbivores, and therefore widespread in areas with large-herbivore communities, include the creation of mud wallows, dust pits, and animal trails, with effects on arthropod communities, fire patterns, and river ecosystem functioning."

"There is direct paleobiological evidence for such engineering effects by extinct late-Quaternary megafauna, for example proboscidean trackways and large burrows made by ground sloths and, potentially, giant armadillos," the paper added.

The paper emphasized the need for better conservation efforts for large mammals currently on the Earth, and also suggested "rewilding" or reintroducing megafauna to restore lost ecological functions.

"Our results highlight the need for active conservation and restoration efforts. By reintroducing large mammals, we can help restore ecological balances and support biodiversity, which evolved in ecosystems rich in megafauna," Svenning told Study Finds .