Wed. Apr 24th, 2019

The first human who conquered an island | Science

The first human who conquered an island | Science

View of the island of Luzon (Philippines).

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The finding of Homo luzonensis, a new human species that lived on the island of Luzon (Philippines), poses a question as interesting as it is difficult to answer: how could it get there?

The fossils found include a bone of the foot that is at least 67,000 years old and other bone remains and teeth that go back at least 50,000 years. In a nearby valley were found stone tools characteristic of primitive humans with an age of 700,000 years. This island has been separated from the continent by hundreds of kilometers of deep sea for at least two and a half million years, an impregnable barrier for any human species except for the Homo sapiens or, at least, that was thought until now.

Florent Détroit, researcher at the National Museum of Natural History in Paris and co-discoverer of the new species, does not close the door on these hominids having the courage and curiosity necessary to launch themselves into the sea. Many experts do not think that Homo erectus, the probable ancestor of the new species discovered, "was intelligent enough to cross the sea on purpose, but we have more and more evidence that they settled on several islands in Southeast Asia, so it is probably not an accident" , propose. "In addition, it is impossible for a population to settle on an island making a single trip, it took several arrivals with several individuals of both sexes to prosper the population," argues the paleoanthropologist.

The theory is supported by the existence of another member of our genre, the Homo floresiensis, who also arrived by sea to the Indonesian island of Flores and there suffered an evolutionary process of dwarfism until being reduced to one meter in height with a brain of about 400 cm3 (the sapiens we have about 1,300).

Excavations in the Callao cave (Philippines) where 'H. luzonensis'.
Excavations in the Callao cave (Philippines) where 'H. luzonensis'.

Most experts believe that these two species reached their destinations on board natural rafts. "You have to imagine the mighty rivers that flow through the tropical forests of Southeast Asia and that after a storm or a tsunami drag a mass of logs and fallen leaves," he explains. Antonio Rosas, paleoanthropologist of the CSIC. "The hominids would have gone up and the currents did the rest. These natural rafts are the most plausible explanation for how primates came to South America from Africa about 23 million years ago. They also explain the arrival of certain reptiles to the Galapagos Islands and mammals to the island of Madagascar, "he points out. It is an enigma how long some of those journeys lasted and how the animals survived them.

María Martinón, director of the National Research Center on Human Evolution, provides another argument against the primitive hominids were navigators. "We have no evidence that the Flores and Luzón hominids were curious or what has been called Wanderlust [un impulso fuerte por el viaje y la exploración]", Explain. "Proof of this is that there is no evidence of movement between islands. It is very likely that once they reached those islands they were trapped. The sets of tools that have been found are quite nonspecific and simple. In general it is accepted that they consumed mostly terrestrial fauna but that the inability to develop sophisticated fishing technologies may be one of the reasons why they have not been very mobile populations or with great dispersion capacity, "he adds.

Most experts believe that these two species reached their destinations aboard natural rafts

This eagerness to discover new territories beyond the ocean would be reserved for sapiens, as well as the art of greater complexity, such as that of the caves of Altamira, in Spain, or Chauvet and Lascaux, in France, all after the arrival of the sapiens to the continent about 40,000 years ago. Of those same dates are the first evidences of navigation in deep waters in Asia associated to Homo sapiens to catch tuna. Unlike the Homo above, the sapiens they would have been the first to live almost exclusively from the consumption of fish, which pushed them to master navigation. Also at this time-about 35,000 years ago-appears the rock art on Sulawesi Island, neighboring Flores. Flores's hobbit had gone extinct some 15,000 years before, just when the first sapiens They came to the archipelago.

Reconstruction of 'Homo erectus' with the engraving made in a shell.
Reconstruction of 'Homo erectus' with the engraving made in a shell.

Not even the Neanderthals, the human species that evolved in Europe and who are considered beings very similar to us, with its own ornaments and art, were given to navigation, highlights Jean-Jacques Hublin, an expert in the study of this species at the Max Planck Institute for Evolutionary Anthropology, in Leipzig (Germany). "Apparently even the Neanderthals who lived in present-day Italy did not cross to Sicily, despite their proximity," he explains.

There are still many unknowns about the cognitive abilities of the Homo erectus. He had a cranial capacity of about 1,100 cm3 and a complexion very similar to ours, perfect for walking and running upright. His is the merit of being the human species that has existed for a longer period of time, nine times more than the sapiens. Its origin goes back to Africa about two million years ago. From there it came out 1.8 million and in a record time it reached Europe and Asia. His is also the first engraving made by a human: a zigzag line made on a mollusk shell that had probably served him before food. This finding was made on the island of Java where, in this case, he had come walking down a dirt corridor that later covered the sea. For now, sapiens we are still the first navigators.


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