Waterfall Bluff paleoenvironmental survey reveals leopard seals far from Antarctic waters

Waterfall Bluff Rock Shelter (WB), Eastern Cape Province (ECP), South Africa, has sustained and continuous human presence spanning from Late Marine Isotope Stage 3 (ca. 39ka to 29ka) to mid-Holocene (ca. 8ka). Contains archaeological deposits indicating occupation. The first leopard seal (Hydrurga leptonyx) specimens from Pleistocene and Holocene zooarchaeological assemblages along the South African coast were recently discovered at this site.

Our paper was published in the South African Journal of Science.

Leopard seal ecology

Leopard seals are marine apex predators whose habitat is usually confined to ice floes on Antarctic and sub-Antarctic islands. They require ice floes to ambush their prey, most of which consists of krill. However, they are also known to hunt penguins, pinnipeds, fish, and cephalopods.

To date, there have been only a few sightings of leopard seals, both living and dead, in South Africa, the earliest being in East London, Eastern Cape Province (ECP) in 1946. The second sighting occurred more than 20 years later in 1969 in Hout Bay.

A dead leopard seal was reported to the East London Museum (ECP) in 1994, and a live specimen was most recently seen at Cob Rock (ECP) in 2014. The most recent sighting was in 2021, when a live specimen was seen twice. , once in Cape Town and once in Iserfontein (Western Cape), after which sightings ceased.

Recently, we discovered leopard seal teeth in WB Last Glacial Maximum (LGM) (estimated BP 22,560-19,340 years) deposits. This makes it the first leopard seal recovered from a Pleistocene and Holocene zooarchaeological assemblage along the South African coast.

Understand the scene and findings

The WB is located approximately 24 meters above the modern shoreline next to the Murambomukuru River Falls in the ECP. It consists of two successive sedimentary layers: light brown coarse sand (LBCS) dated to 37.6±4.2 ka and shell-rich clay dated by a Bayesian 14C accelerator mass spectrometry model from It is divided into quality sand (SRCS). Calorie blood pressure 11ka to caloric blood pressure 10,5ka.

What makes this site particularly important is its consistent proximity to the coastline during both glacial and interglacial periods.

Southern Africa currently has few coastal sites dating back to the terminal Pleistocene. Humans occupied such places at the time, but many have been destroyed or remain undiscovered. This rarity is due to constant fluctuations in sea level, which resulted in biased preservation of the Ice Age coastal archaeological record.

However, because the WB is located adjacent to a very narrow continental shelf, it has survived and preserved records documenting repeated human occupation over thousands of years. This site is likely to have been particularly desirable for humans because of its proximity to the coast, providing access to marine food and multiple terrestrial resources.

It has been hypothesized that such sites would have been occupied by humans elsewhere in southern Africa, such as the Paleo-Aglas Plain. However, these records are now underwater, making WB one of the few archaeological sites that provides insight into human occupation and behavior during the Ice Ages and Interglacials.

We report preliminary results on the faunal analysis conducted in 2021 and its impact on the paleoenvironment of the WB. Although our sample size is small, the interpretation provides compelling insights into the local paleoenvironment and human exploitation behavior.

WB paleoenvironment and its influence

The site presents a persistent mosaic environment capable of supporting all major vegetation types and provides evidence of systematic exploitation of both marine and terrestrial resources by hunter-gatherers.

The site’s location and stable environment would have made it particularly desirable for hunter-gatherers to live in, as they would have had a variety of resources at their disposal, regardless of their surrounding environment.

Both the SRCS and LBCS formations are home to a variety of terrestrial mammals that require different habitats to survive, such as eland (Taurotragus oryx), duiker (Sylvicapra grimmia), and African buffalo (Syncerus afer). , indicating the presence of mixed bushy animals and the African buffalo (Syncerus afer). Grassland environment throughout the site.

Additionally, the presence of possible remains of fish, seals, shellfish, and barnacles in the oldest sediments (LBCS) suggests that during the Ice Age, people probably actively moved away from the coast, even though the coast was about 8 km away. This indicates that they were harvested in the This sustained use of marine resources indicates the importance of the coastal environment to early human communities, even at a time when coasts were far away, and perhaps even in times when coasts were remote. would have required more effort.

We identified leopard seal teeth from this LBCS deposit. This tooth was identified by the distinctive triple-cusped crown used to sift through krill, distinguishing it from the more common fur seal teeth typically found in this region.

Leopard seals are incredibly dependent on the frigid waters surrounded by ice floes for their survival, not only for hunting, but also for breeding and food. Individuals far from their home range are usually lost, starved, or sick.

It is possible that this leopard seal was one such lost individual, but given that local sea surface temperatures were on average 3 degrees Celsius below current levels, it is unlikely that these Antarctic predators Conditions may have been favorable for expanding its range northward.

The increase in ice floes due to these low temperatures in northern regions and the blocking of certain krill spawning grounds in Antarctica will force some leopard seals to live closer to the coast of South Africa than they currently do. It may have become possible. Additionally, the location’s proximity to a river estuary may have washed inland nutrients into the ocean, helping to maintain ocean nutrients that supported the marine animals the leopard seals preyed on.

Given that the West Coast was about five miles from the coast during this Ice Age, leopard seal teeth would have had to be brought to the refuge by humans. The presence of leopard seal teeth indicates that the climate was much colder and may also indicate that humans were more familiar with these animals during the LGM, perhaps taking them to shelter. enough to obtain and transport it as food.

The availability of all the animals mentioned above suggests how adaptive and diverse the survival behavior of early hunter-gatherers was, taking advantage of the resources provided by predator and prey species. There is also a possibility that

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I have a Ph.D. candidate at the University of the Witwatersrand. Since 2018, I have been researching archeology with a focus on zooarchaeology, rock art, and isotopes. My interest lies in uncovering the interactions between humans and animals throughout history. I hope to advance current research on the South African 8.2k event and contribute to filling the considerable knowledge gaps with my work. I aim to become a knowledgeable and internationally recognized archaeological researcher, and am actively working towards publishing the results of my doctoral research and presenting them at academic conferences.