Scientists have discovered fossils of an ancient, tiny species of human
in an isolated part of Indonesia. They are bones from what they say is a
smaller version of the now extinct immediate ancestor to modern humans.
Some observers call it a surprising twig on our family tree, one that
co-existed with modern humans until relatively recently, long after their
normal-sized archaic counterparts disappeared.
The remote eastern Indonesian Island of Flores is an exotic place, with
large lizards known as Komodo dragons and remains of extinct dwarf elephants and miniature humans.
It is the discovery of the chimpanzee-sized humans that is causing
excitement among scientists. Australian researchers report in the journal
Nature that they found the bones of an adult female who stood just one
meter tall with a head the size of a grapefruit. Since submitting the
paper for publication, they found the remains of five or six more of these
wee (small) people, who lived as recently as 12,000 years ago, just before
the dawn of civilization.
"In evolutionary terms, 12,000 years is just yesterday," said Peter
Brown, a University of New England researcher who admits to being flabbergasted when he realized these
tiny archaic people had a brain one-fourth the size of modern humans.
"My colleagues reported that when I measured the size of the brain of
this skeleton and they were observing, I went pale and my jaw dropped to
my knees because people with this brain size were supposed to have become
extinct more than three million years ago, but here we had a small-bodied
human relative with a very small brain surviving until the relatively
recent past, like we have only just missed them," he said.
Mr. Brown says the bones are not those of the three million-year-old
pre-humans to which he referred. Rather, they belong to a small newer
human thought to be our modern species most immediate ancestor, Homo
erectus. But the size of the creature has earned it the right to be its
own species. Mr. Brown's team calls it "Flores Man."
But Homo erectus was much larger, so how did Flores Man become small?
The Australian team believes the full-sized erectus people arrived on
Flores 840,000 years ago, perhaps from Java, after a million-year
migration out of Africa. This view is based on the dating of stone tools
found on Flores in an earlier excavation.
Mr. Brown believes that over time, the species shrank on the isolated
island.
"It underwent similar selection processes that happen to many other
mammals on islands," said Peter Brown. "In the absence of large
predators() and with reduced calories and a heavy covering of rain forest,
it became much smaller in body size."
Evidence gathered with Flores Man suggests the tiny species made its
own tools and hunted, like Homo erectus. Remains of a dwarf elephant
called Stegodon were near the human bones.
But unlike Homo erectus, which died out by at least 40,000 years ago
and maybe earlier, Flores Man stayed around a lot longer. The Australians
believe a volcano eruption finally killed them off 12,000 years ago, as
modern humans were populating the Americas. This belief is based on the
dating of ash layers with the bones.
Scientific reaction to the discovery has been enthusiastic.
"Breathtaking" is the word used by University of Cambridge anthropologist
Robert Foley. At the Natural History Museum in London, Christopher
Stringer calls it remarkable, not only for the size and duration of Flores
Man, but also because early humans managed to get to the remote island.
"This island is a lot further away than Java," said Christopher
Stringer. "Humans could have gotten to the island of Java. At times of low
sea level, Java was connected to the rest of southeast Asia. But the
islands beyond Java, including Flores, are separated by deep water, so it
was not thought that ancient humans could have got across that deep
water."
That implies that Homo erectus had mastered the technology of boats. As
for their diminutive descendants, Mr. Stringer says they are another
example of the variety of humans that once existed.
"It shows us that human evolution, even in the recent past, was
complex," he said. "There were many different species and nature was
conducting its own evolutionary experiments with early humans."
The Australian researchers suggest other remote Indonesian islands
could be hiding similar surprises and plan to dig on them to find
out. |