A MAJOR mystery surrounding tiny ancient human cousins nicknamed “Hobbits” has finally been solved.
Scientists say they’ve cracked a main puzzle about how the 3-foot-tall species came to evolve.
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Officially named Homo floresiensis, the “Hobbits” share a distant and indirect common ancestor with our own species.
They’re nicknamed after the iconic miniature humanlike beings famously penned by J.R.R Tolkien in The Hobbit and The Lord of the Rings.
But unlike Tolkien’s fictional Hobbits, Homo floresiensis was very much real.
“Homo floresiensis lived from about 700,000 to 60,000 years ago in the rainforests of Indonesia, partially contemporaneous with our own species,” said Professor Tesla Monson, of Western Washington University.
Read more on ancient ancestors
“Aptly nicknamed Hobbits, Homo floresiensis were short-statured, at just over 3 feet (1 meter) tall, and had a chimp-size brain.”
Evidence was found in 2003, and the discovery was announced to the world by scientists in 2004.
And it caused experts to question the assumption that brains had been increasing in size over the past several million years, Monson explained.
Now scientists at Western Washington University have studied skulls and teeth to come up with a new theory on “how the Hobbits evolved to be small”.
They scooped up data for teeth abd brain size for 15 different fossil species across the human family tree.
This spanned an enormous five million years of evolution – and helped to solve the Hobbit mystery.
“Wisdom teeth have gotten proportionally smaller as brain size has gotten larger throughout human evolution, for most species,” Monson said.
“Overall, human relatives with relatively larger wisdom teeth are more ancient and had smaller brains.”
She said that more recent groups like the Neanderthals had relatively smaller wisdom teeth compared to their others – as well as larger brains.
And this relationship allowed researchers to make sense of brain size for fossils with just a few teeth.
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Teeth are strong survivors, surviving in the fossil record far better than other parts of the body.
And although large brains usually link to small wisdom teeth, the Hobbits are an exception.
“The wisdom teeth of the Hobbits are small proportional to the other molars – the typical pattern for members of genus Homo,” Monson explained.
“But their brains are also small, which is quite unusual.”
A timeline of life on Earth
Here’s a brief history of life on our planet
- 4.6billion years ago – the origin of Earth
- 3.8billion years ago – first life appears on Earth
- 2.1billion years ago – lifeforms made up of multiple cells evolve
- 1.5billion years ago – eukaryotes, which are cells that contain a nucleus inside of their membranes, emerge
- 550million years ago – first arthropods evolve
- 530million years ago – first fish appear
- 470million years ago – first land plants appear
- 380million years ago – forests emerge on Earth
- 370million years ago – first amphibians emerge from the water onto land
- 320million years ago – earliest reptiles evolve
- 230million years ago – dinosaurs evolve
- 200million years ago – mammals appear
- 150million years ago – earliest birds evolve
- 130million years ago – first flowering plants
- 100million years ago – earliest bees
- 55million years ago – hares and rabbits appear
- 30million years ago – first cats evolve
- 20million years ago – great apes evolve
- 7million years ago –first human ancestors appear
- 2million years ago – Homo erectus appears
- 300,000 years ago – Homo sapiens evolves
- 50,000 years ago – Eurasia and Oceania colonised
- 40,000 years ago – Neandethal extinction
Monson and her team discovered that the body side of the Hobbits “likely shrank from a larger-bodied Homo ancestor”.
And this happened by “slowing down growth during childhood”.
The study showed that the Hobbits were on track for bigger brains like humans while in the uterus, so before birth.
But a “slowing down” then occurred in childhood, which influenced their skeletal shape and size.
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Monson says that their small size was actually a benefit.
“The small body size of Homo floresiensis was likely an adaptation to the unique conditions of their island environment on Flores.
“Evolving small body size as an adaptation to living on an isolated island is known as insular nanism.
“There are many examples of other mammals becoming small on islands over the past 60 million years.
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“But one of the most relevant examples is the dwarf elephant, Stegodon sondaarii, that lived on Flores and was hunted by H. floresiensis for food.”
She continued: “Both Homo floresiensis and Homo luzonensis, another short, island hominin from southeast Asia, likely evolved very short stature because of the ecological effects of limited food availability.
“And lack of large predators, which tends to characterise island habitats.”
And even though the Hobbit’s had smaller brains, they were still “highly capable”, Monson believes.
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