The extinction of cave bear

READING PASSAGE 1

You should spend about 20 minutes on Questions 1-13, which are based on ReadingPassage 1 on pages 2 and 3.

Herve Bocherens, an evolutionary biologist at theUniversity of Tubingen,Germany, says hiscolleagues find his research methods a littlecrude’. He dissolves 30,000-year-old animalbones in hydrochloric acid, which is strong enoughto burn through metal, soaks the bone solution inlye, cooks it at about 200 degrees Fahrenheit andfreeze-dries it, until what’s left is a speck ofpowder weighing less than one one-hundredth ofan ounce. The method may be harsh, but the yieldis precious – the biography of a cave bear as toldthrough its chemical components. Bocherens is at the forefront of research on the bear, a European species that died out 25,000 years ago. Peoplehave been excavating cave bear remains forhundreds of years-in the Middle Ages, themassive skulls were attributed to dragons – but thepast decade has seen a burst of discoveries abouthow the bears lived and why they became extinct.An abundance of bones has been found fromSpain to Romania in caves where the animalsonce hibernated. ‘Caves are good places topreserve bones,and cave bears had the goodsense to die there,’ Bocherens says.

Along with mammoths, lions and woolly rhinos,cave bears (Ursus spelaeus) were once amongEurope’s most impressive creatures. Malesweighed up to 1,500 pounds, 50 per cent morethan the largest modern grizzly bears. Cave bearshad wider heads than today’s bears, and powerfulshoulders and forelimbs. But the relationshipbetween humans and cave bears has beenmysterious. Were humans prey for the bears, orpredators? Were bears the object of worship or fear?

Initially cave bears shared the continent of Europe,more than 100,000 years ago,with Neanderthal, aprimitive species of humans. Modern humansarrived in Europe about 40,000 years ago, andwere soon aware of the bears. They painted images of the animals on cave walls, and carved their likeness in fragments of mammoth tusk. The walls of France’s Chauvet cave are painted withlions, hyenas and bears; dating back 32,000 years. These are perhaps the oldest paintings in the world. The painters weren’t the cave’s only occupants. The floor is covered with 150 cave bear skeletons,and its soft clay still holds paw prints. Mostdramatically, a cave bear skull was perched on astone slab in the center of one chamber,placeddeliberately by some long-gone cave inhabitant’There’s no way to tell if it was just curiosity thatmade someone put a skull on the rock, or if it hadreligious significance,’ says Bocherens.

Another discovery, hundreds of miles to the eastof Chauvet, would shed light on the relationshipbetween cave bears and humans. The SwabianJura is a limestone plateau in southwesternGermany that is riddled with caves. A steel gateguards the Hohle Fels cave from vandals and curiosity-seekers. Floodlights in the cave’s mainchamber illuminate the ceiling, vaulted like a cathedral above 5,000 square feet of floor space long ago, as shown by the bones and tools that archaeologists have found, cave bears and human beings sought shelter here from winterweather.

In 2000, University of Tubingen paleobiologistSusanne Munzel unearthed a bear vertebra with atiny triangular piece of flint embedded in it. Theflint was likely a broken spear point, hard evidence of a successful bear hunt 29,000 years ago Munzel also found bear bones that had clearly been scraped by stone tools. Evidence for bearsbeing a food source for early humans was shownby cut marks on skulls and leg bones where theflesh had been cut away. Many of the bones werefrom babybears,perhaps caught while hibernating.

Cave bears disappeared not long after humans spread throughout Europe, and one theory is that hunting led to the bears’ extinction. HerveBocherens’ test tubes may hold the clues Running his white powder through a mass spectrometer, he identifies different isotopes, orchemical forms, of elements such as carbon and nitrogen that reflect what the bears were eating and how quickly they grew. After studyinghundreds of bones from dozens of sites in Europe,Bocherens has found that cave bears ate mainlyplants.

This would haveparticularlymadebearsvulnerable to the last Ice Age, which began around 30,000 years ago. This Ice Age shortened or eliminated growing seasons, and alteredthedistributions of plant species across Europe. Cavebears began to move from their old territories,according to a DNA analysis of teeth found nearthe Danube River. The cave bear population therewas relatively stable, with the same geneticpatterns showing up generation after generationBut about 28,000 years ago, newcomers withdifferent DNA patterns arrived- a possible sign ofhungry bears suddenly on the move.

But changes in the climate can’t be solely to blamefor the bears’ extinction. According to the lateststudy, by Erik Trinkaus and his colleagues at theMax Planck Institute, cave bear populationsbegan a long, slow decline 50,000 years ago-wellbefore the climate began to change. The newstudy supports a different explanation for the cavebears’ demise. As Neanderthals, and then agrowing population of modern humans moved intothe caves of Europe, cave bears had fewer safeplaces to hibernate. An acute housing shortagemay have beenthe final blowfor thesemagnificent beasts.

Questions 1-6

Do the following statements agree with the information given in Reading Passage 1?

In boxes 1-6 on your answer sheet, write

TRUE if the statement agrees with the information FALSE if the statement contradicts the information NOT GIVEN if there is no information on this

1 Bocherens’ findings on cave bears involve measuring the length of complete bones.

2 Bocherens was the first person to conduct analytical research on cave bears in a laboratory.

3 Cave bears have been extinct for 25,000 years.

4 At one time people thought the excavated remains of bears were those of dragons

5 Modern grizzly bears are similar in size to cave bears.

6 Neanderthals understood cave bear behaviour better than modern humans did

Questions 7-13

Complete the notes below.

Choose ONE WORD ONLY from the passage for each answer.

Write your answers in boxes 7-13 on your answer sheet.

Research into the existence and disappearance of cave bears

Evidence from the Chauvet cave in France

Paintings on the walls include bears.
Over a hundred 7. __________ of cave bears together with paw prints were found on the floor of the cave
The 8. __________ of a cave bear was found in a prominent position in the cave.

Evidence from the Hohle Fels cave in the Swabian Jura in Germany

Bones and tools found in the cave indicate it provided 9. __________ for both bears and humans

Susanne Münzel’s findings

A spear point in the vertebra of a bear indicates that a hunt had taken place.

Marks on the bones of bears indicate the removal of flesh

Hervé Bocherens’ findings

Isotopes from the bones indicate that 10. __________ were the cave bears’ preferred food.

Factors leading to the disappearance of the cave bear

Climate change
- The Ice Age changed vegetation growth in 11. __________
- Bears were forced to migrate.
- Support for the above explanation comes from a study of changes in the DNA in the 12. __________ of the population of cave bears near the Danube River at this time
Human population expansion
- Competition from Neanderthals and modern humans for caves may have reduced opportunities for cave bears to 13. __________