A study sheds light on how an “elephant graveyard” could have been created at a site in southern Spain over a million years ago: The results of investigations into sediment structures suggest that there were quicksand traps on the banks of a former lake. They probably proved fatal to some southern elephants and were thus able to serve as a source of food for “light-footed” carnivores. Fossilized feces and tool remains indicate that these were giant hyenas and early humans of the era. They may also have competed for access to the mountains of meat, say the researchers.
The Fuente Nueva 3 site, which is located around 100 kilometers east of Granada, has been the focus of research for some time: the earliest known traces of representatives of the Homo genus in Western Europe were discovered there. These are sharp-edged stone tools from the Oldowan stage of development, which are dated to up to 1.4 million years ago. The excavations also revealed numerous unhewn stones that were probably used to break bones. They may also have been used as projectiles to drive away giant hyenas (Pachycrocuta brevirostris), of which numerous traces were also discovered at the site.
During the excavations in Fuente Nueva 3, researchers also frequently came across the remains of so-called southern elephants (Mammuthus meridionalis), which were widespread in southern Europe in the late Early Pleistocene. This has given the site the reputation of being an “elephant graveyard”. Some of the remains also contained flint fragments and fossilized traces of giant hyena droppings, suggesting that the two species competed for the carcass resources. But why were there so many dead elephants in Fuente Nueva 3? This question is now being shed light on by the results of the research conducted by researchers led by Paul Palmqvist from the University of Malaga.
Evidence of quicksand on the lake shore
As part of their study, the researchers examined the material from sediment layers at the site in more detail, in which the remains of southern elephants, human tracks and fossilized hyena droppings were found. As the team reports, the analyses showed that one soil layer in particular was characterized by a very small particle size. As the researchers explain, the very fine material was the subsoil in the shore area of the former lake that was once located at the site. This is probably why the material was also slightly soaked with water.
The researchers concluded that the subsoil had characteristics that could be used to describe it as quicksand. “Quicksand is known to be a deadly trap for an animal: after it gets caught in the material, the viscosity of the sediment increases due to the separation of the quicksand into two phases: a water-rich phase and a sand-rich phase. This causes an animal trapped in quicksand to sink deeper and deeper as it tries to escape the trap,” the authors write.
The heavy southern elephants could have become particularly effectively stuck in the fine material due to the combination of high weight and relatively small foot area, the researchers explain. They point to examples from today: It is known that African elephants sometimes get stuck in soft ground and ultimately die as a result. Specifically, the team highlights a case that was observed in 2019 in the Mana Pools National Park in Zimbabwe: During a drought, an elephant cow and calf went too far into a muddy waterhole and both ended up getting stuck there. They ended up becoming a meal for a horde of spotted hyenas.
Half-submerged food sources
According to the researchers, the results of the investigation now suggest that something similar happened over a million years ago at the Fuente Nueva 3 site: Southern elephants repeatedly got caught in the quicksand trap on the banks of the former lake. Their half-submerged carcasses then attracted carnivores, which did not sink into the material due to their lower weight and lightness of foot. Both giant hyenas and early humans were thus able to use the abundant food sources, as the remains of stone tools and the fossilized excrement traces (coprolites) in the area of the elephant fossils show.
It can therefore be assumed that the two species encountered each other regularly. “The coprolites and flint fragments partially overlap in their distribution, which suggests competition between hominins and hyenas for elephant carcasses,” the researchers write. According to them, the study sheds new light on the food supply strategies of the first human populations that settled in Western Europe in the late Early Pleistocene, as well as on possible conflicts with animal competitors.
Source: University of Malaga, specialist article: Journal of Iberian Geology, doi: 10.1007/s41513-024-00241-1