Going Under Down Under: Early People At Fault In Australian Extinctions

Science News ^ | 1-19-2007 | Sid Perkins

[blam]

Going Under Down Under: Early people at fault in Australian extinctions

Sid Perkins

A lengthy, newly compiled fossil record of Australian mammals bolsters the notion that humanity's arrival on the island continent led to the extinction of many large creatures there.

Archaeological evidence suggests that people arrived in northern and western Australia about 50,000 years ago (SN: 3/15/03, p. 173: Available to subscribers at http://www.sciencenews.org/articles/20030315/note10.asp). By 5,000 years later, about 90 percent of the continent's mammals larger than a house cat had gone extinct, says Gavin J. Prideaux, a paleontologist at the Western Australian Museum in Perth. Casualties of that era include several species of kangaroos and wombats as well as marsupials that filled the ecological niches elsewhere populated by lions, hyenas, hippos, and tapirs.

By unearthing and cataloging specimens from a group of fossil-rich caves about 300 kilometers southeast of Adelaide, Prideaux and his colleagues assembled a nearly complete record of the past 500,000 years. Most of the 62 species of nonflying mammals on the list fell into the caverns via sinkholes, but some remains were brought in by owls that roosted there.

Scientists had compiled a long-term climate record for southeastern Australia by analyzing the caves' stalactites. Those structures formed and grew when rainfall was plentiful but not during dry spells.

During most of the past 500,000 years, the number and diversity of mammal fossils found in the Australian caves decreased only during intervals when the local climate was dry. When moisture returned, so did the animals. The only exception is the die-off of mammals between 50,000 and 45,000 years ago, the team reports in the January Geology.

Those extinctions occurred at least 25,000 years before the most recent ice age began. "The climate was stable then, and mammals really shouldn't have been going extinct," says coauthor Richard G. Roberts, a geochemist at the University of Wollongong in Australia. "The only thing that's new during that period is people," he adds.

Scientists are debating how people might have caused the extinctions. Some researchers argue that the new inhabitants drastically altered Australian ecosystems by burning the landscape (SN: 7/23/05, p. 61: Available to subscribers at http://www.sciencenews.org/articles/20050723/note11.asp). However, large species may have died off gradually when people preyed on the mammals' offspring faster than the animals reproduced, says Roberts.

The fossil record compiled by Prideaux and his colleagues shows that "the mammal fauna was resilient through time, despite climate fluctuations," says David W. Steadman, a paleontologist at the University of Florida in Gainesville. Changes in mammal populations during times of climate change "were nothing like those that occurred after people showed up," he notes.

"To think climate caused these extinctions is [now] untenable," comments Gifford H. Miller, a geologist at the University of Colorado at Boulder.

If you have a comment on this article that you would like considered for publication in Science News, send it to editors@sciencenews.org. Please include your name and location.

[blam]

GGG Ping.

[RightResponse]

Yeah, all this... and they're basing it on what the stalagtites tell them?

[org.whodat]

Stalagtites tell them?

Are they any relation to the Klingon's?? :)

[Harmless Teddy Bear]

Obviously where the Atlanteans had their hunting preserve.

[LibFreeOrDie]

How can this be true? I thought indigenous peoples treated Mother Earth and all wildlife as sacred! /s

[From many - one.]

Among the aboriginal tribes are several versions of a fire myth including burning up the landscape.

Here's one:
Some Myths and Legends of the Australian Aborigines: How Fire was Stolen from the Red-Crested Cockatoo

http://www.sacred-texts.com/aus/mla/mla19.htm

An interesting feature is the red marked bird, found in many European and other mythologies. Perhaps one of the oldest myths in the world.

[Old Professer]

The ultimate solution to all the planet's problems is the elimination of the prime predator; no more people, no more problems.

[Old Professer]

Do you get your upper dentures and your lowers confused too? (Stalactites and stalagmites)

[Ciexyz]

Oz ping.

[org.whodat]

(Stalactites and stalagmites)

Do you often get confused about who, or whom cut and pasted what. See post #3. Does that help?

[Old Professer]

Yeah, I guess it would have been better to send it to blam but you were holding the door open.

[Old Professer]

Okay, okay, the right response would have been to send it to RightResponse, my knees are getting sore.

[blam]

"Yeah, I guess it would have been better to send it to blam but you were holding the door open."

LOL. See the last two highlighted lines under the article.

[SunkenCiv]

Thanks Blam.

To all -- please ping me to other topics which are appropriate for the GGG list. Thanks.

Please FREEPMAIL me if you want on or off the
"Gods, Graves, Glyphs" PING list or GGG weekly digest
-- Archaeology/Anthropology/Ancient Cultures/Artifacts/Antiquities, etc.
Gods, Graves, Glyphs (alpha order)

[DieHard the Hunter]

The arrival of mankind has had a documented effect on the survival of large and small creatures in NZ. It would not surprise me if it were the same deal in OZ.

In New Zealand, the arrival of the Maori saw the eventual complete extermination of the Moa, which was a huge flightless bird (think Ostrich but much, much bigger: 400 lbs). The were hunted to extinction. This in turn led to the demise of the Haast Eagle who used to hunt moa, which was the largest raptor on earth at the time (8 - 10 ft wingspan).

As well, they brought with them the kiore, or native rat. This and later rat migrations cleaned up many of the smaller native animals, many of them unique to NZ and found nowhere else.

The Kea, a flightless mountain parrot, seems to have survived the arrival of mankind by adaptation: it has a curious habit of perching on the backs of sheep and dining on the kidneys and surrounding fat, eventually killing the sheep. (yeah, an omniverous flightless parrot -- they used to think dogs were killing sheep in this fashion, then they caught it all on film: it is amazing to watch).

It is speculated that this is exactly what they used to do with moa: it would have had to be adaptation because there were no sheep in NZ before the arrival of the Europeans.

(Kea are extremely clever, inquisitive and destructive birds. They live in the ski hills in South Island. It is not uncommon to find your car in a shambles after your afternoon's skiing: Keas are notorious for pulling the rubber from around the windows and windshields, and generally causing havoc. They also apparently have some abilities to reason: some say they are as intelligent as higher apes.)

[Fred Nerks]

New evidence that Tasmanian tigers once roamed Australia's mainland has come to light in the world's largest concentration of rock art, adding weight to calls for its legislative protection. Twelve rock carvings of the extinct thylacine have been found on the Burrup peninsula, a rugged 20km-long expanse on the northwest Pilbara coast of Western Australia. The discoveries by archaeologist Ken Mulvaney, some made as recently as last month, double the number of thylacine images found among ancient Aboriginal rock carvings scattered across 2000 Burrup sites. As many as 300,000 individual drawings, featuring animal and human figures, have been etched into boulders...

http://rockartnews.blogspot.com/2006_05_01_rockartnews_archive.html

and not one mega-fauna among them...seems odd, doesn't it?

[SunkenCiv]

interesting.

---

Kea, Mountain Parrot

The Kea, New Zealand's cheeky mountain parrot is a bird with "attitude". Raucous and inquisitive, the bird is not afraid of humans and puts on colourful displays for visitors to South Island ski fields and mountains.

---

[Cold Heart]

They only based the climate claims on the stalactite analysis.
Fossil study gave them the rest of the information that bolstered the notion from previous studies.

[DieHard the Hunter]

They are an interesting bird. They jump and can glide for short distances: it's not really "flying", it's "falling with style." Mostly they walk.

I saw one in a Christchurch sanctuary: he had figured out that if he squawked into one end of a drainage a pipe, the amplified noise came out at the other end, about 20 feet away. And that this noise would surprise people walking by the other end of the pipe: a huge noise apparently coming from nowhere.

Seemed to be his favorite trick.

They have relatives in Australia: both have been, in their time, considered pests and hunted for bounty. Now, they are protected. Both are considered quite dangerous and should be appreciated from a distance.

I believe they are the only parrot known to have killed people. I find it hard to imagine: they are about the size of a football. That said, if any bird that size could kill someone, the Kea would be intelligent enough to know how to do it, and certainly has a handy enough beak and pair of claws.