1-5 million year old footprints human ancestor coexistence

1.5-Million-Year-Old Footprints Reveal Coexistence of Two Human Ancestor Species

The Discovery Near Lake Turkana

On a sun-scorched savanna teeming with life over a million years ago, near the shores of present-day Lake Turkana in Kenya, two distinct hominin species may have coexisted, foraging for survival.

The Significance of the Fossilized Footprints

By examining 1.5-million-year-old fossils unearthed from an ancient lakeshore, scientists have identified the first recorded instance of two hominin footprints from the same period. This discovery, researchers assert, will advance our understanding of human evolution and the interplay of cooperation and competition between species.

Defining Hominins

"Hominin" refers to a modern classification that represents a subset of hominids, encompassing all extinct and extant species within the human lineage following the divergence from great ape ancestors approximately 6 to 7 million years ago.

Insights from the Ancient Footprints

This discovery, as detailed in Science, provides compelling evidence of the coexistence of diverse hominin species, who shared territories while navigating predators and environmental challenges in ancient Africa.

The Species Involved

According to the researchers, the tracks were created by hominins belonging to Homo erectus and Paranthropus boisei, the two most prevalent human species of the Pleistocene period.

Expert Analysis by Craig Feibel

"The discovery of their footprints on the same surface, formed within a narrow time frame, positions the two species at the lake margin, sharing the same habitat," explained Craig Feibel, study co-author and professor in Rutgers' Department of Earth and Planetary Sciences and Department of Anthropology.

The Process of the Discovery

Drawing on his decades of research in northern Kenya since 1981, a region renowned for its fossil wealth, Feibel utilized his stratigraphy and dating expertise to confirm the fossils' geological age at 1.5 million years. He further analyzed the depositional context of the footprint surface, pinpointing the trackmakers' activity to within a few hours and demonstrating that the tracks were formed directly in the soft sediments where they were discovered.

The Timing of the Footprints

As Feibel explained, the hominins might not have interacted, but their movements along the shore occurred just hours apart.

Footprints as Key Evidence of Ancient Behaviors

Although skeletal remains have traditionally been the cornerstone of human evolution studies, fossil footprints now provide compelling insights into the development of human anatomy, locomotion, and ancient behaviors.

Kevin Hatala's Contribution

Explained Kevin Hatala, lead author of the study and an associate professor of biology at Chatham University in Pittsburgh, Pennsylvania.

Hatala, who has studied hominin footprints since 2012, remarked that fossil footprints offer vivid glimpses into the lives of our ancient relatives, bringing them to life in extraordinary detail.

"These data allow us to explore how individuals from millions of years ago navigated their environments, interacted with each other, and potentially other animals—insights unattainable from bones or tools."

Analyzing Anatomical Patterns

Hetala, a specialist in foot anatomy, identified distinct anatomical and locomotion patterns in the s pecies' foot prints. Using advanced 3D analysis methods, he and his co-authors distinguished between the two sets.

A Unique Framework for Foot print Analysis

Rebecca Ferrell, a program director at the National Science Foundation, stated that biological anthropology constantly seeks innovative methods to infer behavior from fossils, and this study exemplifies that effort.

Innovative 3D imaging Technology

Utilizing innovative 3D imaging technology, the researchers devised a unique framework for examining footprints, enhancing our understanding of evolution and the interplay between cooperation and competition.

The Path to Discovery

Describing the discovery as 'a bit of serendipity,' Feibel noted that the fossil footprint were identified in 2021 when a team, organized by Louise Leakey—a descendant of the celebrated Leakey lineage—uncovered fossilized bones at the site.

Field Team and Excavation Details

Under Cyprian Nyete's direction, the field team—primarily local Kenyans with specialized training—searches the area after rainstorms. They detected fossils on the surface and proceeded to excavate for their source.

The Initial Discovery

While removing the upper sediment layer, Richard Loki, one of the excavators, observed large bird tracks and later discovered a hominin footprint. Leakey organized a team to excavate the site in July  2022.

Understanding the Coexistence of Homo Erectus and Paranthropus Boisei

Feibel explained that the coexistence of these human species has been theorized for years. The fossil record shows that Homo erectus, a direct human ancestor, lasted for an additional million years, while Paranthropus boisei went extinct within a few hundred thousand years, and the reasons for this remain unclear.

Physical and Behavioral Characteristics

Both species were characterized by upright postures, bipedal movement, and remarkable agility. However, their interactions—cultural reproductive—remain largely unknown.

Trace Fossils and Their Significance

Feibel explained that the footprints are notable because they belong to the category of 'trace fossils,' which can include things like footprints, nests, and burrows.

Comparing Trace Fossils to Body Fossils

Unlike body fossils such as bones and teeth that are evidence of past life and may be displaced by water or predators, trace fossils reveal behavioral evidence.

According to Feibel, trace fossils are immobile and cannot be moved.

Conclusion: A Groundbreaking Discovery

Feibel remarked that the discovery proves conclusively that two distinct hominin species were on the same surface, potentially only hours apart. "The idea that they lived at the same time might not be surprising, but this is the first time we've proven it. It's a significant finding," he said.

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