Bajondillo Cave

Bajondillo Cave (in Spanish, Cueva Bajondillo) is an archaeological site on the south-central coast of the Iberian Peninsula, in the Spanish city of Torremolinos outside of the city of Malaga. It is 127 km from the Strait of Gibraltar. It is referred to alternately, for archaeological purposes, as "southern Iberia".

The cave is thought to have been used a shelter for early modern humans and Neanderthals.

Archaeological excavations
An archaeological excavation of Bajondillo Cave was completed in 2011. The study revealed important information regarding the early arrival of modern humans, including their diets and behaviors. Some of the findings contradict earlier assumptions about the timing of the arrival and crossover between Neanderthals and anatomically modern humans ("AMH") in this region. Among other points of contradiction are previous misperceptions about the systematic consumption of shellfish among Neanderthal. The unique position and elevation of this cave offers an exceptional location for early hominid occupation, as well as for the preservation of fossils and other remnants. While no human remains were found, there were large quantities of both lithic and non-lithic fragments and artifacts that were capable of examination and stratigraphic and other date-stamping, evidencing a long period of continuous hominid cave dwelling from at least 150 ka BP.

Findings
The 2011 excavation produced, among other significant findings, the most important data on record regarding the collection and consumption of shellfish by early hominids in the Iberian Region. The height and location of the cave make it clear that the large mollusk and mussel remnants were deposited by humans, as the cave was never below or at sea level. Indeed, the Bajondillo Cave is important in understanding the connection between Iberian Neanderthals and AMHs because many Neanderthal dwellings are inaccessible as they are now underwater. Moreover, many of the bones, shells, and other findings evidence intentional fracturing with force and/or thermoalteration consistent with cooking.

The cave was excavated in several phases and twenty archaeological levels were identified. The first seventeen levels were documented according to stratigraphic sequencing. A total of approximately 5.7 meters of sediment was excavated. Over 10,000 shellfish and related fragment samples were collected and catalogued with relative certainty to species, genus and / or class evels. Thousands more handmade tools we recovered and labeled. Extensive testing was performed, resulting in twenty-nine “absolute dates” revealing contiguous early hominid occupancy from Middle Paleolithic Era (MIS 6) to the Neolithic (MIS 1).

Primary site researchers from the University of Seville Miguel Cortes-Sanchez, et al. arduously defend the structural integrity of the site and its excavation and refute challenges to the technical accuracy of their findings. Specifically, the researchers posit that “improved radiocarbon protocols have …yielded reliable dates for Bajondillo," while rejecting claims of “displacement erosion” and cross-level contamination within the site, whether naturally-occurring or manmade.

History
According to researchers, stratigraphy within the cave indicates a lengthy chronological-cultural succession ranging from “Middle Paleolithic, Aurignacian, Gravettian, Solutrean, Magdalenian, Epipaleolithic and Neolithic” eras. Twenty levels of well-defined excavation  further indicates that this cave was occupied by early hominids almost continuously for nearly 200,000 years.

The unique position of this cave relative to the sea below made it an ideal protective shelter for humans. There are significant fossils, physical remnants and artifacts indicating epochs of occupation, tool making, use of fire, and the cooking of several species of mammals. There is significant evidence of consumption of shellfish.

The excavation was performed in phases. Beginning in 1989, upon discovery, seventeen levels were excavated to a depth of 5.6m. Later phases exposed an additional 0.006 m of sediment bringing the number of “bones, shells, and hearths” and other remnants to over 10,000 pieces.

Physical structure
The cave is a large rock structure approximately 30 m long, with a 30 m high travertine formation. The rock formation is consistent with other limestone dwellings commonly found in that area of the Iberian Peninsula.

The Bajondillo Cave is currently 50 m from the coastline and +15 m above mean sea level. Over the epochs of its occupation, the cave varied from 0. km to 3 km distance from the coast. However, during the most relevant period of occupation from 150 ka BP to approximately 10 ka BP the cave was a convenient distance of approximately 00 m from the shore.

Significance
Excavations at the site have resulted in two significant findings: Shellfish collection by Neanderthals, and that the arrival and replacement of Neanderthals by anatomically modern humans 5,000-10,000+ years later than previously believed.

Shellfish
The first significant finding was a large collection of mussels and other mollusk shells, often with taphonomic features [6] including intentional fragmentation and charred markings indicative of cooking, beginning in 155 ka BP. As Miguel Cortes-Sanchez and colleagues explain:

"In view that systematic collection of shellfish has been increasingly recognized as a crucial element of human adaptation to aquatic ecosystems and evidence associated with the appearance of Homo sapiens, the synchronicity of these findings raise the possibility of a behavioral convergence existing in the two hominine lineages triggered by causes yet to be determined."

Although there have been numerous “hints’ [2] and reports of evidence of Neanderthal shell fishing in the area, the Bajondillo Cave provides the first scientifically documented proof of early, systematic consumption of shellfish by non-modern humans. A principal theory states that “the expansion of the diet to incorporate foods of marine origin constitutes a key adaptation … a major shift … in the cognitive capabilities” of modern humans over Neanderthals. The significance of the Bajondillo Cave findings is that not only were Neanderthals capable of collecting shellfish for consumption in a deliberate and systematic manner, it is no longer evident that there is a clear correlation between the consumption of shellfish (requiring organization and technical skills) and the arrival of modern humans. Furthermore, there may be other unexplored convergences between Neanderthal and Anatomically Modern Humans.

Replacement of Neanderthals
The second significant finding is that anatomically modern humans appear to have replaced Neanderthals much later in the southern Iberian region than previously believed. As researchers at the university of Seville observe,

"The final replacement of Neanderthals …in western Europe is usually dated to around 39,000 years ago… It is claimed that the southern Iberian region documents the late survival of … Neanderthals to about 32,000 years ago … [However the] Bajondillo Cave … calibrates the replacement  to between 45-43,000 years ago, raising questions about the late survival of Neanderthals in southern Iberia. "

Additional postulations based upon findings in the Bajondillo Cave confirm that the dispersal of AMHs was faster and more westwardly expansive than previously believed. Earlier research indicates that AMHs only dispersed quickly into unpopulated or low-populated areas, a position which is challenged by these findings. Furthermore, evidence at Bajondillo reinforces prior research that “coasts and coastal lowlands” were a more temperate and hospitable route for early-AMH “dispersal and colonizing events” in many places throughout the world. As primary researchers Cortes-Sanchez, et al. eloquently state:

"[Data from] Bajondillo make perfect sense … at the time when the last Neanderthal populations were dwindling in Iberia, ecological frontiers were being broken by anatomically modern humans across many parts of the planet."

This evidence invites questions, such as whether Neanderthals and modern Homo sapiens coexisted for greater periods than previously understood [, ]; whether the Strait of Gibraltar was actually a path out of Africa for modern humans [,  ], and confirming the importance of the Mediterranean Coast for modern humans to progress into Europe. [, ]. Studies regarding the Strait of Gibraltar as a method of transit between Neanderthals and is noted as an especially “promising area of research” and one which, proven or disproven, will offer anthropological clarity.