Hippo's island life helps explain dwarf hobbit (w/Video)

May 07, 2009
Hippo's island life helps explain dwarf hobbit
This dwarf hippo skull from the Museum’s collections is nearly 3000 years old and helped scientists explain the small brain of the hobbit. Image: Natural History Museum

Ancient Madagascan hippos have shed light on the origins of the small brain of the 1-metre-tall human, known as the hobbit, scientists at the Natural History Museum report in the journal Nature today.

By examining the skulls of extinct Madagascan hippos, Museum scientists discovered that dwarfed mammals on islands evolved much smaller brains in relation to their body size.

So Homo floresiensis may have had a tiny because it lived on an island. This is something which has been at the heart of the debate of the hobbit’s origins, whose remains were uncovered on the Indonesian island of Flores in 2003.

This video is not supported by your browser at this time.
Ancient Madagascan hippos have shed light on the origins of the small brain of the 1-metre-tall human, known as the hobbit. Video: Natural History Museum

The team suggests that the hobbit became a dwarf after its ancestor became isolated on the large island of many years ago.

‘The discovery of a small human from the island of Flores with normal facial proportions but a brain the size of chimpanzee has baffled scientists,’ explained Natural History Museum palaeontologist, Dr Eleanor Weston, who led the research.

‘It could be that its skull is that of a dwarfed mammal living on an island. Looking at pygmy hippos in Madagascar, which possess exceptionally small brains for their size, suggests that the ‘hobbit’ was a dwarf resulting from its H. erectus ancestors being isolated on the island in the past.’

Analysing hippos

Madagascar has many diverse habitats and in the past, has been the home to at least 3 species of hippo.

The team studied species of extinct Madagascan hippos and their mainland ancestor, the large common hippopotamus.

One of the specimens used, from the Museum’s mammal collection, was a nearly 3000-year-old dwarf hippo skull belonging to the extinct Hippopotamus madagascariensis.

Brain calculations

Hippo brain-body scaling trends were calculated from the relationship of brain to size.

‘We found that the brain sizes of extinct dwarf hippos were still up to 30% smaller than you would expect by scaling down their mainland African ancestor to the dwarf’s body size’ explains Dr Weston.

‘If the hippo model is applied to a typical H. erectus ancestor the resulting brain capacity is comparable to that of H. floresiensis.’

The brain of Homo floresiensis is the smallest yet known for any hominid, at around 400 mL.

A first for brain size

Although the phenomenon of dwarfism on islands is well recognised in large mammals, an accompanying reduction in brain size, as Dr Weston and Museum palaeontologist Professor Adrian Lister found, has never been clearly demonstrated before.

Energy use of brain

It may be advantageous to the survival of animals that become isolated on islands with unique environments, not only to become dwarfs, but also to reduce the size of their brain.

‘The brain is a costly organ that uses a lot of energy,’ says Dr Weston. ‘Whatever the explanation for the tiny brain of floresiensis relative to its body size, it’s likely that the fact that it lived on an island played a significant part in its evolution,’ concludes Dr Weston.

Source: American Museum of Natural History (news : web)

Explore further: Wyoming cave with fossil secrets to be excavated

add to favorites email to friend print save as pdf

Related Stories

More 'Hobbit' bones are discovered

Oct 11, 2005

Paleontologists digging on the remote Indonesian island of Flores say they've found more bones of Homo floresiensis, a tiny hominin species.

Incredible journey through 'hobbit' brain

Mar 03, 2005

Florida State University professor and chair of anthropology Dean Falk led an international team of scientists on an incredible virtual journey through the tiny brain of an 18,000 year-old hobbit-sized human. What they found ...

New analysis shows 'hobbits' couldn't hustle

May 06, 2009

A detailed analysis of the feet of Homo floresiensis—the miniature hominins who lived on a remote island in eastern Indonesia until 18,000 years ago -- may help settle a question hotly debated among paleontologists: how si ...

Anthropologist confirms 'Hobbit' indeed a separate species

Jan 29, 2007

After the skeletal remains of an 18,000-year-old, Hobbit-sized human were discovered on the Indonesian island of Flores in 2003, some scientists thought that the specimen must have been a pygmy or a microcephalic ...

Recommended for you

West US cave with fossil secrets to be excavated

14 hours ago

(AP)—For the first time in three decades, paleontologists are about to revisit one of North America's most remarkable troves of ancient fossils: The bones of tens of thousands of animals piled at the bottom ...

Radar search to find lost Aboriginal burial site

Jul 22, 2014

Scientists said Tuesday they hope that radar technology will help them find a century-old Aboriginal burial ground on an Australian island, bringing some closure to the local indigenous population.

User comments : 0