The brain size of a dwarf hobbit can be explained by the hippo island's life

The ancient Madagascan hippopotamus has helped to find out why the hobbit (a dwarf with a height of 1 meter) is very small in size, according to reports from scientists at the Natural History Museum on the sheet. Nature was released on May 7.

With the inspection of the extinct Madagascan skull, scientists at the Museum found that during evolution, the brains of mammal dwarf mammals gradually became smaller than their body size.

Thus, the cause of Homo floresiensis (scientific name of the hobbit) has a small brain because they live on the island. The question of small brain size has always been a hot topic of debate regarding the origins of hobbits, the strain of people found the remains on Flores Island, Indonesia, in 2003.

The team thought that the hobbits became like dwarfs after their ancestors were Homo erectus (erect erectus) isolated on the big island of Madagascar many years ago.

'Detecting tiny human fossils on Flores Island with a normal face composition but brain size equal to chimpanzees has resisted scientists,' explains Dr Eleanor Weston, the lead researcher.

'This skull may be the skull of a mammal dwarf animal that lives on the island. By observing the dwarf hippopotamus that lives in Madagascar has a particularly small brain, we can conclude that the hobbits are dwarf-like species that evolved from Homo erectus through the process of isolation on the island many years ago. '

Analysis of hippopotamus

Madagascar has a diverse habitat, and in the past it used to be home to at least 3 species of hippopotamus.

The dwarf hippopotamus with a lifespan of 3000 years in the Museum's collection has helped scientists explain the small brain size of hobbits.(Photo: Natural History Museum, London)

The team looked at three species of extinct Madagascan hippos and their ancestors on land - a common hippopotamus.

One of the samples used, taken from the Museum's mammal collection, is a 3000-year-old dwarf hippopotamus of the extinct hippopotamus Hippopotamus madagascariensis.

Calculate brain size

Trends in determining the ratio of brain-body are calculated based on the relationship between brain and skull size.

'We have found that the brain size of extinct dwarf hippopotamus is still 30% smaller than the results obtained when dividing their ancestral body size in Africa and muscle size. The dwarf hippopotamus, explains Dr. Weston.

'If the aforementioned hippo model is applied to a typical H. erectus person, then the corresponding brain size of H. floresiensis is obtained.'

So far the Homo floresiensis human brain has the smallest size of all known human strains, only about 400 ml.

The first study on brain size corresponds

Although dwarfism on islands is only common in large mammals, the reduction in brain size corresponds to Dr. vWeston and the professor, discovered by paleontologist Adrian Lister, is something that has never been proven before.

Energy consumption of the brain

Both dwarfing and decreasing brain size are beneficial measures for the survival of isolated organisms on the island with a special habitat.

'The brain is a body that consumes a lot of energy,' said Dr. Weston. 'Whatever the reason for the small size of the brain compared to the body, it must be that the existence of an island is crucial to the evolution of this breed,' said Dr. Weston. comment.

References:
Weston et al.Insular dwarfism in hippos and a model for brain size reduction in Homo floresiensis.Nature, 2009;459 (7243): 85 DOI: 10.1038 / nature07922