Scientists have finally discovered because the flower hobbit is so small

The size of the wisdom teeth in all human species is the smaller the larger the brain size. In all, except in the Homo floresiensisthe hobbit of flowers. This exception has given scientists clues about why they are so small: island dwarfism.

Until the discovery of Homo floresiensisscientists assumed that the evolution of the human line was essentially defined by increasing brains.

Through a process called encephalizationhuman brains have evolved to be relatively bulkier than one would be expected based on the corresponding body size.

This proportionally larger brain is, according to anthropologists, which allowed us to us and our relatives to perform more complex taskshow to use fire, manufacture and handle tools, raise art and tame animals.

But these theories had to be completely reviewed When archaeologists announced our fossil cousins, the 2004 scientific publication.

O Homo floresiensis He lived between about 700,000 and 60,000 years ago in Indonesia’s tropical forests, partially contemporary of our own species.

Properly called Hobbitsos Homo floresiensis They were of low stature, just over 1 meter highand had a brain the size of a chimpanzee.

This discovery has shaken the assumption that brains have been increasing size over millions of years and generated confusion about what distinguishes the most recent human relatives of the genre Homo of our older ancestors.

A new study on skulls and teeth Homo floresiensisconducted by Tesla Monson e Andrew Weitzanthropology teachers at Western Washington University, now offers a innovative theory on how hobbits will have evolved to have a small body.

In 2023, the two researchers participated in a workshop for biological anthropologists who study youth specimens in the fossil record, and began to analyze the brain size changes throughout human evolution.

In a previous work on the proportions of molars, Monson and Weitz had launched new perspectives on the Evolution of pregnancydemonstrating that fetal growth rates are closely linked to molar proportions in primates.

Now they intended to verify if it would be possible to find a relationship between the dental proportions and brain size Among our fossil relatives, the two investigators explain in an article no.

Rebuild the brain size from the teeth

In his, whose results were presented in an article recently published in the Annals of Human Biology, the researchers gathered data on the size of the tooth and the brain of 15 fossil species of the human genealogical tree, covering about 5 million years of evolution.

In a way paradoxical, the third molars, known as wisdom teethhave become proportionally smaller as the brain increased Size throughout human evolution, in most species.

Overall, human relatively larger human relatives are older and have smaller brains. More recent species, such as neanderthals, had third molars relatively smallerin relation to other teeth, and larger brains.

This relationship allows investigators Estimate the brain size of fossils Incomplete, possibly preserved only as a few isolated teeth.

How the teeth are composed predominantly by inorganic matter, survive much more often In the fossil record than other parts of the body, representing the vast majority of recovered paleontological materials. Being able to infer brain size from just a few teeth is therefore a extremely useful tool.

Today, scientists recognize that the Brain and Tooth formation It is intrinsically linked during pregnancy. And in most species, larger brains are correlated with smaller wisdom teeth.

The exception in the Homo genre is the Homo floresiensiso hobbit. Hobbits wisdom teeth are small in proportion to other molars – The typical standard of members of the Homo genre. But Your brains are also smallwhich is quite unusual.

They exist Two main forms of brain size decrease: Through a slowdown of growth during pregnancy, before birth, or through a slowdown of growth after birth during childhood.

How teeth develop early in pregnancy, a slowdown on growth rates during pregnancy tends to affect the shape and size of the teeth, or even their occurrence.

A later slowdown, during childhoodinfluences the shape and skeletal size of other ways, as different parts of the body develop in different moments.

The results of the study by Monson and Weitz suggest that the body size of the Homo floresiensis probably decreased from a larger ancestor through slowdown of growth during childhood.

The small wisdom teeth of the hobbits indicate that at least in uteroThey were on their way to develop proportionally larger brains – the registered hall of humans and their relatives. Any brake that has delayed brain growth It probably occurred after birth.

In fact, this is the same mechanism by which some modern human populations of low stature have adapted to their local ecological conditions.

Islands

Homo Floresiensis’s small body size was probably a adaptation to the unique conditions of your environment insular in flowers. Evolve into a small body as an adaptation to live on an isolated island is known as insular dwarfism.

There are many examples of others mammals that have become small on islands over the last 60 million years. One of the most relevant examples is the dwarf Stegodon sinneriiwho lived in flowers and by H. Floresiensis for food.

Both Homo floresiensis like the Homo luzonensisanother low stature hominid from Southeast Asia will have evolved to a very low stature due to ecological effects of limited food availability and the absence of large predators, typical characteristics of island habitats.

Like brain size and body size are closely connected, the evolution of the body inevitably affects cerebra evolutionl. Among modern humans, larger individuals have larger brains, and smaller individuals have smaller brains.

But people with smaller brains They are by no means less intelligent than people with larger brains. The body size variation determines the brain size; It is not a measure of cognitive capacity.

The hobbits of the islands manufactured tools, hunted large prey For their size, and probably used the fire.

Monson and Weitz’s study thus supports the theory that its small body size resulted from a Springs of growth during childhood.

But this process will have probably had little impact on brain function Or in cognitive capacity: the hobbits were small but highly capable, the two investigators say.