The extinction of the cave bear
Read The extinction of the cave bear, an IELTS Reading practice passage. Hervé Bocherens, an evolutionary biologist at the University of Tübingen, Germany, says his colleagues find his research methods a little 'crude'. He dissolves 30,000-year-old animal bones in hydrochloric acid, which is strong…
Passage preview
Hervé Bocherens, an evolutionary biologist at the University of Tübingen, Germany, says his colleagues find his research methods a little 'crude'. He dissolves 30,000-year-old animal bones in hydrochloric acid, which is strong enough to burn through metal, soaks the bone solution in lye, cooks it at about 200 degrees Fahrenheit and freeze-dries it, until what's left is a speck of powder weighing less than one one-hundredth of an ounce. The method may be harsh, but the yield is precious - the biography of a cave bear as told through its chemical components. Bocherens is at the forefront of research on the bear, a European species that died out 25,000 years ago. People have been excavating cave bear remains for hundreds of years- in the Middle Ages, the massive skulls were attributed to dragons but the past decade has seen a burst of discoveries about how the bears lived and why they became extinct. An abundance of bones has been found from Spain to Romania in caves where the animals once hibernated. 'Caves are good places to preserve bones, and cave bears had the good sense to die there,' Bocherens says.
Vocabulary from this passage
10 words worth learning before you sit the test, each with the sentence it appears in.
- abundance noun
A very large quantity of something, usually rendering it more than sufficient for needs
An abundance of fossilized remains allows scientists to accurately reconstruct prehistoric biological profiles.
- acute adjective
Present or experienced to a severe, intense, or critical degree
An acute shortage of nesting grounds triggers extreme competitive behaviors among regional fauna.
- alter verb
To change or modify in character, form, composition, or chronological trend
Rapid ice age transitions radically altered the geographic distributions of major plant species.
- demise noun
The end, failure, or death of something that was previously powerful or significant
Anthropogenic territorial encroachment often accelerates the eventual demographic demise of vulnerable wildlife.
- excavate verb
To make a hole or channel by digging, especially as part of an archaeological exploration
Archaeologists continue to excavate ancient cave sites to gather clues about early human life.
- hard evidence noun
Indisputable facts or physical indications that definitively validate a theory, assertion, or hypothesis
The discovery of a flint point embedded in the bone provided hard evidence of hunting.
- hibernate verb
To spend the winter in a dormant, state of inactive metabolic slowdown or deep sleep
Many large mammals seek secure geological formations to hibernate safely during harsh winters.
- isotope noun
Each of two or more forms of the same chemical element containing equal numbers of protons
Scientists analyze stable carbon and nitrogen isotopes to trace the dietary habits of extinct species.
- solely adverb
Not involving anyone or anything else; only, exclusively, or entirely based on one element
The evolutionary collapse of an apex predator cannot be attributed solely to shifting global temperatures.
- vulnerable adjective
Susceptible to physical or emotional attack or harm; inadequately protected against adverse shifts
Species with specialized diets are exceptionally vulnerable to sudden environmental and climatic disturbances.