Hobbit hominins of Flores island, why extinct?

This video is a 2017 documentary on the hobbit hominins of Flores island in Indonesia.

From National Geographic, 12 March 2019:

‘Hobbit’ human story gets a twist, thanks to thousands of rat bones

An abundance of rodent remains adds new clues to the fate of the tiny human relative Homo floresiensis on the Indonesian island of Flores

By Paige Madison

The limestone cave of Liang Bua, on the Indonesian island of Flores, is widely known as the hobbit cave, the site where the surprisingly tiny and enormously controversial extinct human relative Homo floresiensis was discovered. But to the scientists who excavate there, the site is known as something else entirely: the rat cave.

“The first time I went to the excavations at Liang Bua, I remember watching the bones coming out of the ground and being amazed at how it was almost all rat”, recalls Matthew Tocheri, the Canada Research Chair in Human Origins at Lakehead University.

Now, Tocheri and an international team of scientists have examined the rat bones and found evidence for major shifts in their past populations—including one around 60,000 years ago, when hobbit remains started vanishing from the cave.

“Sixty-thousand years ago is precisely when the hobbits’ presence began to decline, before disappearing from the site altogether,” says Wahyu Saptomo, head of conservation and archeometry at the Indonesian National Research Centre for Archaeology.

That means the discovery, which is being reported in the Journal of Human Evolution, not only paints a previously unknown picture of the paleoecology around Liang Bua, it also could help answer some of the biggest lingering questions concerning what happened to the hobbits.

Measuring rats

When H. floresiensis burst onto the paleoanthropological scene in 2003, its small brain and strange, primitive traits sparked debates about where it fit within the human family tree. As scientists hunted for clues to this mystery, the hobbit’s environment began to come into focus, with digs at the site revealing a cast of prehistoric characters almost as bizarre as the hobbit itself, from giant storks to cow-sized elephant relatives and ancient komodo dragons.

Yet, the most plentiful creatures found beneath the surface of the cave floor by far are rats, which make up 80 percent of the identifiable bones at the site.

The rats of Flores aren’t your average rodents; this is as true today as it was when H. floresiensis roamed the landscape. One of the rat species alive today is as large as a small dog, and while this giant rat usually garners the spotlight, it is only one of many species preserved at Liang Bua, each one varying in size, behavior, and food preference.

Of all the species on Earth, “rodents are the most diverse group of mammals”, remarks study leader Elizabeth Veatch, a graduate student at Emory University who is affectionately known by the research team as Miss Tikus (Indonesian for “rat lady”). And in paleoanthropology sites, these variations can convey information about the local ecology and environment through time.

Rats are exceptionally useful for painting the picture of prehistoric life at Liang Bua because their bones appear continuously in the cave sequence. While hobbits, stegodons, and others come and go, the rats persist throughout the roughly 190,000-year stretch preserved under the cave floor.

“Homo floresiensis and modern humans are simply occasional guests that check in and check out for limited stays,” Tocheri points out. (Find out more about the hunt for hobbit DNA.)

Using the rats’ diversity and temporal persistence, and with partial funding from the National Geographic Society, Veatch and Tocheri measured more than 12,000 rat bones, grouped them in size classes, and tracked the relative abundances of each class throughout the stratigraphic sequence. That’s when a striking signal emerged: Medium-size rats that prefer more open habitats dominated the site until about 60,000 years ago, when the bones give way to smaller, more forest-adapted rats.

This shift, the team hypothesizes, reflects a change in the environment surrounding the cave with “more open habitats giving way to more closed ones”, says Jatmiko, a study coauthor and researcher at the Indonesian National Research Centre for Archaeology.

Hobbit migration?

This ecological shift doesn’t just effect only the hobbits, the team suggests: “H. floresiensis wasn’t alone in this departure—the remaining large species followed suit. By 50,000 years ago, all traces of hobbit, stegodon, vulture, stork, and komodo dragon were gone from the cave,” Saptomo says.

Previously, scientists hypothesized that the large fauna on Flores went extinct. “The signal from the rats, however, suggests H. floresiensis’ departure from Liang Bua may simply be because they—and the others—left in search of more open environments,” Veatch says. (On the neighboring island of Sulawesi, scientists also found stone tools that may have belonged to a hobbit relative.)

In essence, the hobbits and their giant animal neighbors didn’t necessarily die out at that time, but may have moved on to more hospitable parts of the island, says coauthor Thomas Sutikna of Wollongong University.

“There is the possibility that some of them still survive after that time somewhere on Flores,” he says.

The team’s analysis is “elegant and careful”, says Bernard Wood, director of the Center for the Advanced Study of Human Paleobiology at George Washington University, who adds that it showcases the need to take many possible interpretations of a given fossil record into account. “This study is yet another example of the folly of equating the end of the fossil record of a taxon at a local site, or sites, with its extinction across a much larger region,” he says.

For instance, the results could mean that the hobbit species lingered into the more recent past—and may have even come into contact with our ancient ancestors. Modern humans (Homo sapiens) appear to have arrived on the island by about 46,000 years ago, and a possible extension of the hobbits’ presence on Flores suggests that they might have encountered modern humans elsewhere on the island.

Resolving such questions will require additional discoveries—in this case, at Liang Bua and elsewhere on Flores. If scientists are fortunate, they will find more caves and sites containing the bones of H. floresiensis. And if they are even luckier, they will also uncover lots and lots of rat bones to help flesh out what exactly happened in the last days of this lost human relative.

Komodo dragon discovery on Flores, Indonesia

This 2014 BBC video is about Komodo dragons.

From BirdLife:

Komodo Dragons found in unprotected Indonesian IBA

By Martin Fowlie, Wed, 18/12/2013 – 11:09

A team including staff from BirdLife Partner Burung Indonesia has confirmed the presence of the Komodo Dragon, the world’s largest lizard, in the west of Flores Island, Indonesia. The discovery adds further urgency to the BirdLife Partnership’s campaign to gain formal protection for the Mbeliling Important Bird and Biodiversity Area (IBA), which includes the forests where the giant lizards were found.

Komodo Dragon Varanus komodoensis is classed as Vulnerable on the IUCN Red List. Camera traps recorded at least 12 individuals in the Mbeliling forest in the extreme west of Flores, opposite the small islands of Komodo and Rinca, which are the known strongholds of the Komodo Dragon. The Komodo National Park, a UNESCO World Heritage site, includes these islands and a section of the Flores coast, but the Mbeliling IBA lies outside its boundaries.

As recently as 2004, Komodo Dragons were found at sites on the north and south coasts of Flores, but the survey work by Burung Indonesia and others provides the first confirmation that they also survive in the west.

“We hope these discoveries will be widely publicised and help our efforts to protect this irreplaceable biodiversity-rich forest area”, said Burung Indonesia’s communications officer, Irfan Saputra.

BirdLife has identified Mbeliling as an Important Bird and Biodiversity Area because of its populations of threatened restricted range species, including the Critically Endangered Yellow-crested Cockatoo Cacatua sulphurea, and Flores Hanging-parrot Loriculus flosculus, Flores Monarch Monarcha sacerdotum and Flores Crow Corvus florensis, which are all considered Endangered.

Without formal protection, the forest of Mbeliling IBA is being cleared to create agricultural land, which soon becomes exhausted, leading to further forest clearance. BirdLife has been working with the people of 27 villages around the IBA to make agricultural practices more sustainable, and to restore and enhance soil nutrients using organic farming methods, thereby reducing the pressure on the forests.

Danida, the Danish International Development Assistance funded this work.

With one chomp, a Komodo dragon traps its prey: here.

KOMODO ISLAND CLOSING AFTER DRAGON SMUGGLING Indonesia’s famed Komodo Island, home to the world’s largest lizards, will soon close to tourists following reports of smugglers stealing and selling dragons. The island will be shuttered in January 2020 for a year, a decision fueled by the recent arrests of nine men who allegedly stole 41 Komodo dragons and sold them abroad for $35,000 apiece. [HuffPost]

Aventinus Sadip is the founder of a plant nursery and a farmer’s group restoring forest around the Mbeliling IBA, Flores, Indonesia: here.

New colourful Indonesian fish discovery

Paracheilinus rennyae, photo: Conservation International

By Jake Adams on Nov 06, 2013:

Paracheilinus rennyae, a new flasher wrasse from Flores Indonesia

Paracheilinus rennyae is a new species of flasher wrasse recently described with a very unique and distinct outline to its profile. Looking not unlike the smooth edged Paracheilinus octotaenia from the Red Sea, Paracheilinus rennyae comes from southwestern Flores Island in the Lesser Sunda island chain of Indonesia.

The new species of flasher wrasse from Southern Indonesia is distinguished by a complete lack of fin or filaments extensions, like the Red Sea 8-line flasher wrasse. However, the color pattern and genetic analysis indicates Paracheilinus rennyae is most closely related to P. angulatus from the Philippines and northern Borneo.

Scientific description of this new species: see here.

Pre-hobbit human ancestors of Flores

This video is about the “Hobbit of Flores“.

From Scientific American:

Mar 17, 2010 06:28 PM

Hominins lived on Flores for nearly one million years before hobbit

By Katherine Harmon

Predecessors of the controversial “hobbit” (Homo floresiensis) discovered on the Indonesian island of Flores might have had a longer history there than researchers previously thought.

Although early hominins were presumed to be living on Flores about 800,000 years ago—as evidenced by the discovery of stone tools dated to that time—new finds and analysis push their arrival back another 200,000 years, according to a study in the March 18 issue of Nature (Scientific American is part of Nature Publishing Group). If hominins were present on the island for one million years, as the new findings suggest, that would extend the window of time in which a small primitive human, such as H. floresiensis, which lived about 18,000 years ago, could have evolved.

The group, led by Adam Brumm of the Centre for Archaeological Science at the University of Wollongong in Australia, found some 45 stone artifacts, which the team was able to describe and date. The tools were likely made by early ancient hominin ancestors on the island; it remains unknown if the users of these tools were directly related to H. floresiensis.

Scientists had proposed that the arrival of hominins on Flores precipitated the vanishing of giant tortoise (Geochelone) and pygmy elephant species (Stegodon sondaari) from the area about 800,000 years ago. But an earlier arrival of these individuals now raises doubts about such a direct causation. “It now seems that this extirpation or possible extinction event…were the result of natural processes rather than the arrival of hominins,” noted the researchers, who proposed that climate change, volcanoes or other force might have killed off these animals.

Tracing stone tool clues to discover the earliest date of hominins’ arrival on the island, however, might prove to be difficult, the researchers noted. The sediment at the popular Soa Basin site, which has long been exploited for ancient evidence, appears be too recently deposited to yield artifacts much older than those described in the study. Therefore, concluded the researchers, new clues should “be sought in other parts of the island.”

The Late Pleistocene Flores fauna shows a pattern observed on many other islands. It is neither aberrant nor exclusive, but the result of non-random selective forces acting upon an impoverished and disharmonic insular fauna. By comparing the Flores vertebrate fauna with other fossil insular biotas, it is apparent that the evolution of Homo floresiensis is part of a general pattern affecting all the inhabitants of Pleistocene Flores. Vertebrate evolution on Flores appears to have been characterized by phylogenetic continuity, low species richness and a disharmonic fauna. All three aspects stem from the isolated position of the island and have resulted in the distinct morphological characteristics of the Flores fauna. Evidence reviewed herein shows that features exhibited by H. floresiensis, such as small stature, a small brain, relatively long arms, robust lower limbs and long feet, are not unique, but are shared by other insular taxa. Therefore, the evolution of H. floresiensis can be explained by existing models of insular evolution and followed evolutionary pathways similar to those of the other terrestrial vertebrates inhabiting Pleistocene Flores: here.

‘Hobbit’ was an iodine-deficient human, not another species, new study suggests: here.

Flores bones show features of Down syndrome, not a new ‘hobbit’ human: here.

Homo floresiensis: scientists clash over claims ‘hobbit man’ was modern human with Down’s syndrome. Tiny skeleton from Indonesia’s Flores island is unique ancient species, insist researchers: here.

Hobbits died out earlier than thought. Tiny hominids disappeared from their island about same time Homo sapiens appeared in the region: here.

Homo floresiensis Likely Evolved from Primitive Ancestor in Africa, Researchers Say. Apr 23, 2017: here.

A modern pygmy population living on an Indonesian island near a cave with Homo floresiensis (‘hobbit’) fossils appears to have evolved short stature independently. H. floresiensis was significantly smaller than the modern Flores pygmies, standing about 3.5 feet tall (shorter than the average kindergartener), while modern pygmies average about 15 inches taller. Floresiensis also differed from H. sapiens and H. erectus in their wrists and feet: here.

Siberia: “X-woman”, as the creature has been named, last shared an ancestor with humans and Neanderthals about 1 million years ago but is probably different from both species. She lived 30,000 to 50,000 years ago: here.

A metal pin adorning a military uniform signifies rank; a ring on the left hand’s fourth finger announces matrimony. Most scientists thought that the capability for such symbolic thinking was unique to modern humans, but a new study suggests that it dates back to before the Neandertals: here.

Welcome to the family, Homo sapiens neanderthalensis: here.

Neanderthal Children Were Large, Sturdy: here.

Cozy Neanderthal sleeping chamber in cave contained hearth and grass beds that may have been covered with animal fur: here.

Archaeologists have found a foot bone that could prove the Philippines was first settled by humans 67,000 years ago, thousands of years earlier than previously thought, the National Museum said Tuesday: here.

Ancient New Guinea settlers headed for the hills: First human arrivals rapidly adapted to mile-high forests 50,000 years ago: here.

The early human colonisation of islands might not have been plain sailing. Instead of using boats to deliberately settle on Indonesian islands, hominins may have arrived as castaways, carried on floating debris after floods: here.

Interactive Timeline of Human Evolution: here.