Why Did Ancient Tiny Human Species Homo Floresiensis, “The Hobbits”, Evolve to Be Just Over 3 Feet Tall? — Here’s the Evolutionary Theory

Imagine a species of humans that is as small as a child as an adult, but has survived hundreds of thousands of years. That is exactly what scientists have found on the island of Flores in Indonesia. A hominin named Homo floresiensis, but more commonly known as “The Hobbits”.

They are a species of archaic human whose height is just over 1 meter or around 3ft and 6 inches. But why did they evolve to be so small compared to most other hominins they existed with, like Neanderthals, Homo erectus, and Homo sapiens? Let’s find out.

What We Know About The Hobbits

Homo floresiensis lived on the island of Flores, where the most famous fossils were found in Liang Bua Cave. These remains are dated to be about 100,000 to 60,000 years. However, there are newer discoveries at a site called Mata Menge that show fossils from about 700,000 years ago that belong to a tiny human species, too.

These recent findings suggest the hobbits evolved to be smaller much earlier, and their ancestors may have even been smaller than the last generation before they went extinct. One of the skeletons showed that a grown adult was only about 1.06 meters tall, which is roughly 3 feet and 6 inches.

The hobbits are believed to have a smaller brain than that of modern humans. Based on their skull, it is just about one-third the size of that of adult Homo sapiens. However, despite their tiny brains, they were intelligent enough to develop and use stone tools, and even control fire.

Additionally, this is a human species that has been isolated for hundreds of thousands of years on an island. This is primarily thought to be the reason why they evolve to be over 3 feet tall, a phenomenon known as island dwarfism.

Read more: Phys.org

The Island Dwarfism Hypothesis

Why Were Homo Floresiensis So Small?

One of the most widely accepted theories of why the hobbits evolved to be so small is a phenomenon called island dwarfism, also known as insular dwarfism. This refers to the situation where a species lived on an isolated island, with a limited number of resources, the absence of larger predators, and limited space.

These factors create a circumstance where smaller bodies are advantageous and more likely to survive, such as the stature of Homo Floresiensis. They require less food and water, and it is a lot easier to maintain when the island becomes scarce of resources.

Island dwarfism is not necessarily specific to humans, because large animals on this same island, like elephants, also shrank in size over time. In other words, continents like Asia, Europe, and Africa, having a bigger body, could be a defensive advantage against bigger predators like sabertooth tigers and leopards.

However, the island of Flores is isolated, and most other animals went down in size. Combined with the lack of predators that could hunt humans, there was no significant evolutionary pressure to have a larger body.

Part of this theory was that Homo Floresiensis, or the hobbits, was a descendant of Homo erectus, another human species that likely existed long before them, for nearly 2 million years. It is believed that they arrived on the island of Flores and evolved over many generations to become smaller in response to or triggered by their environment.

Other Theories and What Challenges Them

Although island dwarfism was the main theory and is the most accepted, there are several more ideas that could explain why the hobbits evolved to be smaller. One is that they did not evolve from Homo erectus, but rather from other tiny human species, such as Homo habilis or some type of Australopithecine.

Instead of Homo erectus, who have an estimated size of 4 feet 9 inches to 6 feet 1 inch, these other hominins would already have been of the same stature or smaller than the hobbits. However, this theory lacks evidence that is supported by fossils, plus the increasing amount of proof of island dwarfism makes this theory less accepted.

Another idea states that the fossils found may have originated from individuals with growth disorders or some form of disease that made them smaller than normal. This could explain their smaller brains and bodies.

But, this is also a theory that is not accepted because of the presence of older dated new fossils that suggest that dwarfism began hundreds of thousands of years ago, before the first fossil’s estimated age. So, in other words, it appears to be a result of an evolutionary trend rather than a random variation in genes or a disease.

Read more: NATURE

Why Small Size Helped Homo floresiensis Survive

Concerning Hobbits - The Story of Homo floresiensis ~ with DR KAREN BAAB

So, how did Homo floresiensis survive for hundreds of thousands of years despite their small stature? First, it is better to think that they did not survive despite their size, but rather because of it. They flourished and thrived in that isolated island due to how they evolved.

A smaller body meant a smaller need for energy. They required less food and other resources in an environment that is already limited. So, these smaller humans were able to survive far longer than larger-bodied hominins could, in this specific circumstance.

The brain is one of the most expensive organs to maintain in the human body. But it tends to scale relative to the body size. So the hobbits’ evolution of a smaller brain may have helped reduce their metabolic needs, while at the same time, maintaining the cognition and intelligence similar to other humans. They were capable of creating and using stone tools, controlling fire, and even hunting animals several times bigger than themselves.

Author's Final Thoughts

The small stature of Homo floresiensis at just over 3 feet tall is an asset and not a liability in the isolated island of Flores. The most widely accepted theory for why they evolved to be this size is a phenomenon called island dwarfism.

It refers to a circumstance where there is no significant evolutionary pressure to retain bigger bodies, combined with the limited resources of the environment, it became advantageous to be of smaller stature. This tiny human species highlights just how flexible evolution could be, and that sometimes being small is its own strength.

Read next: How Did Homo Erectus Survive for Nearly 2 Million Years? — Here’s What Researchers Found Out

References & Further Reading

Brown, P., Sutikna, T., Morwood, M. J., et al. (2004). A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia. Nature. https://doi.org/10.1038/nature02999

van den Bergh, G. D., Meijer, H. J. M., Morwood, M. J., et al. (2016). Homo floresiensis-like fossils from the early Middle Pleistocene of Flores. Nature. https://doi.org/10.1038/nature17999

Henneberg, M., Eckhardt, R. B., Chavanaves, S., & Hsü, K. J. (2014). Evolved developmental homeostasis disturbed in LB1 from Flores, Indonesia, denotes Down syndrome and not diagnostic features of a new hominin species. PNAS. https://doi.org/10.1073/pnas.1407382111

Westaway, K. E., et al. (2017). An early modern human presence in Sumatra 73,000–63,000 years ago. Nature. https://doi.org/10.1038/nature23452