My Google Page Rank

Mammoths wiped out by multiple killers


Woolly mammoths were apparently driven to extinction by a multitude of culprits, with climate change, human hunters and shifting habitats all playing a part in the long decline of these giants, researchers say.

Woolly mammoths (Mammuthus primigenius) wandered the planet for about 250,000 years, ranging from Europe to Asia to North America covered in hair up to 20 inches (50 centimeters) long and possessing curved tusks up to 16 feet (4.9 meters) long. Nearly all of these giants vanished from Siberia by about 10,000 years ago, although dwarf mammoths survived on Wrangel Island in the Arctic Ocean until 3,700 years ago.

Scientists have often speculated over what might have driven the mammoths to extinction. For instance, for years researchers suspected that ancient human tribes hunted the mammoths and other ice age giants to oblivion. Others have suggested that a meteor strike might have drastically altered the climate in North America about 12,900 years ago, wiping out most of the large mammals there, the so-called "Younger Dryas impact hypothesis."

Now an analysis of thousands of fossils, artifacts and environmental sites spanning millennia suggest that no one killer is to blame for the demise of the woolly mammoths.

"These findings pretty much dispel the idea of any one factor, any one event, as dooming the mammoths," researcher Glen MacDonald, a geographer at the University of California, Los Angeles, told LiveScience.

*Mammoth database

Scientists investigated the extinction of woolly mammoths living in Beringia, the last refuge of mammoths that nowadays lies mostly submerged under the icy waters of the Bering Strait. To get an idea of woolly mammoth abundance, past climate and other environmental factors, they analyzed samples from more than 1,300 woolly mammoths, nearly 450 pieces of wood, nearly 600 archaeological sites and more than 650 peatlands, compiling their ages and locations to see how these giants and their environments changed over time. They also probed mammoth genetic data found in fossils of the titans.

"There will be people talking about the incompleteness of the fossil record, and there'll always be uncertainties here, no question, but the size of our database is thousands of data points, so I think we can see the general patterns," MacDonald said.
Their results revealed woolly mammoths flourished in the open steppe of Beringia between 30,000 to 45,000 years ago, with its relatively abundant grass and willow trees. The area wasn't as warm then as today, but not as cold as the height of the ice age. "That seemed to be very favorable for mammoths, in terms of abundance," MacDonald said. Humans coexisted with mammoths back then, clearly not driving them to extinction at that time.

Later, during the iciest part of the ice age 20,000 to 25,000 years ago, the "Last Glacial Maximum," northern woolly mammoth populations declined, likely because the area became too barren to be hospitable. However, during that time, the giants became abundant in the warmer interior parts of Siberia.

"There was an old idea that cold glacial conditions like the Last Glacial Maximum were optimal for mammoths," MacDonald said. "That idea now doesn't really hold water."

*Northern refuge

Northern mammoth populations grew after the Last Glacial Maximum, but then dipped again during the Younger Dryas period about 12,900 years ago. Although there is controversy as to what happened at that time, "there was certainly a very rapid and profound cooling of many regions then, followed by rapid warming," MacDonald said. "Did this cause the extinction of the mammoth? Absolutely not. They were still present in far northern sites at the end of the Younger Dryas. Right now it's not quite definitive how great an impact the Younger Dryas had."

The last mammoths seen on the continents were concentrated in the north. They apparently disappeared about 10,000 years ago as the climate warmed and peatlands, wet tundra and coniferous forests developed, environments to which mammoths were poorly suited. The long-lasting proximity between mammoths and humans suggested that our species was perhaps a factor in the beasts' decline, possibly killing off the final island populations of woolly mammoths that went extinct 3,700 years ago.

Overall, these findings suggest the mammoths experienced a long decline due to many factors.
"There was no one event that ended the mammoths," MacDonald said. "It was really the coalescence of climate changeand the habitat change that triggered [it], and also human predators on the landscape at the end."

These findings regarding mammoths could shed light on what species today might face in the future.
"Mammoths faced profound climate change and very profound changes in their habitat and landscape, and also faced pressure from humans," MacDonald said. "Now think about the 21st century, where we're seeing rapid climate change, massive changes in the landscape and certainly pressure from humans on the environment. Species today are facing the same sorts of challenges the mammoths did, but the rate of those changes today are much greater than what mammoths faced."

Future research can focus on other animals once plentiful across Beringia, such as horse and bison. The scientists detailed their findings online June 12 in the journal Nature Communications.

by Charles Q. Choi

Related news items:
Newer news items:
Older news items:

Prev Next Page:

The visitation: proof that Jesus is God

30 Aug 2015 Hits:30

LIFE’S INSPIRATIONS: “…When Elizabeth heard Mary’s greeting, the baby leaped in her womb, and Elizabeth was filled with the Holy Spirit…” (Luke 1:41, the Holy Bible).-ooo-THE MEANING OF THE VISITATION[...] Read more

IN sheep’s clothing, but ravening wolves, inside.

30 Aug 2015 Hits:30

SHARING TIME:IN the secular world, it’s always said, “The voice of the people is the voice of God.”BUT, the Truth is always: “The voice  of God is the voice of[...] Read more

BBL- Malaysia’s diplomatic offspring

27 Aug 2015 Hits:272

No matter how vigorous and passionate Congressman Rufus Rodriguez, the Chairman of the Ad Hoc Committee on the draft Bangsamoro Basic Law (BBL), pushes for the approval of this controversial[...] Read more

Sinkholes threaten Filipinos

27 Aug 2015 Hits:199

LIFE’S INSPIRATIONS: “… the Lord’s anger burns against his people; his hand is raised and he strikes them down. The mountains shake, and the dead bodies are like refuse in[...] Read more

Another bomb explosion in Ayala

27 Aug 2015 Hits:238

Yesterday, August 26, early morning—at about 6:30AM, a bomb was, accordingly, planted in nearby dirt and exploded close in proximity to the house of the Ayala Barangay Captain. This is[...] Read more

“Tug-of-war” on Itu’?

27 Aug 2015 Hits:161

PASSAGE of the Days:“Whosoever was not found written in the book of life was cast into the lake of fire.” Revelation 20: 15. Email: ---****--****“TUG-OF-WAR” ON VM ITU?WHAT is[...] Read more

Poe in Zambo…

26 Aug 2015 Hits:205

Indeed, the election fever is obviously about to start, as before us, prelude appearances or sorties of political personalities, not just locally but also nationally, are starting to pop everywhere[...] Read more

Pacana’s unread speech before jury advocates

26 Aug 2015 Hits:161

LIFE’S INSPIRATIONS: “… All these curses will come on you. They will pursue you and overtake you until you are destroyed, because you did not obey the Lord your God[...] Read more

NASECORE takes cudgel vs. mess-ups in Zamcelco

26 Aug 2015 Hits:162

PASSAGE of the Day:“Search the Scriptures; for in them ye think ye have eternal life: and they are they which testify of me.” (John 5: 39). Email:—****—***—***—**  ZAMCELCO’ NON-TRANSPARENCY[...] Read more

Comprehensive agreement on Bangsamoro violates the human right of Bangsa-Sug (PART I)

25 Aug 2015 Hits:261

In the Comprehensive Agreement (CAB) signed on 27 March, 2014, between the Moro Islamic Liberation Front (MILF) and the Government of the Republic of the Philippines (GRP), the territories of[...] Read more

Who is Danilo Pacana?

25 Aug 2015 Hits:142

LIFE’S INSPIRATIONS: “… `The rains came, the floods rose, and strong winds (howled)…” (Jesus, our God and Savior, in Matthew 7:24-27, the Holy Bible).-ooo-WHO IS DANILO PACANA? You know there[...] Read more

What a bloody Monday

25 Aug 2015 Hits:179

Such a horrible day to meet us with bad news in a Monday morning—to hear a young man gunned down from his own motorcycle service, as early as 6:30 in[...] Read more

(Comelec says:) “Validation of voters in ZC is very slow,”

25 Aug 2015 Hits:150

PASSAGE of the Day:“A feast is made for laughter, and wine maketh merry; but money answereth all things.” Ecclesiastes 10: 19). Email:—****—***—**  TREND OF VOTERS’ VALIDATION IS BADTHE trend[...] Read more

(Comelec says:) “Validation of voters in ZC is very slow,”

25 Aug 2015 Hits:99

PASSAGE of the Day:“A feast is made for laughter, and wine maketh merry; but money answereth all things.” Ecclesiastes 10: 19). Email:—****—***—**  TREND OF VOTERS’ VALIDATION IS BADTHE trend[...] Read more

Alvarez-Nuño alliance crushed Spain’s reign

24 Aug 2015 Hits:335

With all sincerity, I admire the uncommon courage, the extraordinary enthusiasm, and the remarkable degree of youthful dynamism of Hon. VP Elago in spearheading the campaign  for a thorough and[...] Read more

In defense of Enrile bail

24 Aug 2015 Hits:151

LIFE’S INSPIRATIONS: “…maintain justice in the courts…” (Amos 5:15, the Holy Bible).-ooo-WHY IS EVERYBODY YACKING IN THE TORRE DE MANILA CASE? There is something amazing that is happening now in[...] Read more

September events to unfold; Chabacano’s controversial spelling to be discussed at City Council

24 Aug 2015 Hits:146

“Mary is the only woman who is mentioned by name in the (Holy) Qur’an. There is an entire chapter in the Qur’an entitled “Maryam”. She is mentioned 34 times in[...] Read more

Is the no quorum session deliberate?

24 Aug 2015 Hits:142

On the program of Cong. Lilia, in Barangay eMedia last Friday—August 21, she related some of the recent events which transpired in the House of Representatives. She shared the seeming[...] Read more