In a Swedish zoo a chimpanzee called Santino spent his nights breaking up concrete into pieces to throw at visitors during the day. Was he being spiteful? In caves in the US, female bats help unrelated fruit bat mothers if they can't find the right birthing position. Are they being caring? Fifty years ago, these questions would have been largely seen as irrelevant. Animals had behaviours, the behaviours produced measurable outcomes, and science recorded those outcomes. The idea that animals have consciousness, feelings and moral systems was sloppy and sentimental.

But recently that has partially changed. Thanks to research into the behaviour of bats, chimps, not to mention rats, dolphins and chickens, emotions of animals have gone from being a taboo area of investigation to being tentatively explored. It is a change that has in recent years filtered through the scientific strata to a selection of popular science books, such as Mark Bekoff's Wild Justice and Victoria Braithwaite's Do Fish Feel Pain? And in the process it has started a debate that may never be solved by science: can animals be said to have consciousness? 

This debate stimulates a second, much less abstract, one: not of consciousness, but conscience - a person's moral sense of right and wrong that guides their behaviour. In a recent experiment involving cows that had to open a locked gate in order to get food, it became apparent that those that successfully opened the gate themselves showed more pleasure — by jumping and kicking their legs — than those that had to have the gate opened for them. If, as this research seems to imply, cows enjoy problem-solving, what does it mean for the production and consumption of beef?

The observations may not be disputed, but the interpretation of them is. According to Dr Jonathan Balcombe, author of Second Nature, the only logically consistent response to the new research is to stop eating meat. For him, humanity is on the verge of the greatest revolution in ethics since the abolition of slavery. According to Aubrey Manning, Professor Emeritus at Edinburgh University, we should at the very least re-evaluate our view of animal cognition. For him. 'the only tenable hypothesis is that animals do have a theory of mind, but it's simpler than ours.' And according to Professor Euan MacPhail we should just stop anthropomorphising. The three may never be reconciled because the crux of the issue is not so much a scientific disagreement, or even a moral one, but a philosophical one. Given that even defining consciousness is near impossible, can we ever hope to know, in the words of the philosopher Thomas Nagel, what it is like to be a bat? Let alone a bat midwife. 

Balcombe describes a landmark experiment he did that in his interpretation - appears to show that starlings - a type of bird - can get depressed. In a study at Newcastle University, starlings were split into two groups. Half were housed in luxurious cages, with plenty of space and water. The other half were housed in small, barren cages. Initially both groups were fed with tasty worms from one box and unpleasant worms from another, and soon learned to take only from the tasty box. But subsequently when the birds were offered only unpleasant worms, only the ones housed in luxurious cages would eat. It seemed, or at least Balcombe concluded, that being in a nasty cage caused the starlings to be pessimistic about life in general. 

Balcombe, who has worked with animal rights groups, has a clear bias. 'We look back with abhorrence on an era here there was racism,' he says. "Our view about animals will someday be the same. We can't espouse animal rights between bites of a cheeseburger' if he were the only advocate of this view of animal consciousness, it might be easy to dismiss him as an extremist. Unfortunately for those who might prefer to ignore Balcombe, Professor Aubrey Manning is in the same camp. Manning has written a textbook, An Introduction to Animal Behaviour. 'What we are seeing is a pendulum swing,' he says. 'At the turn of the 20th century there were people who made assumptions that animals thought just like us, and there was a reaction against that. Now we are going and you really want to try to avoid the sound of academics with various personal grievances and strong personal opinions.'

31 In the first paragraph the writer suggests that 

A some older animal research would now be seen as unscientific 

B some animals respond too unpredictably to be included in reliable study data.

C some animal research has come to conclusions that are highly questionable. 

D some animal behaviour is difficult to explain through a traditional approach.

32 In the second paragraph, what point is the writer making about the idea that animals

have emotions? 

A It has been confused by many with another issue. 

B It has moved beyond mere academic speculation. 

C It has been fully accepted by the scientific community. 

D It has contradicted another recent proposal on the topic.

33 When the writer mentions cows, he is saying that

A scientists now believe that certain animals have a sense of morality. 

B some animals are fundamentally unsuited to being kept in captivity. 

C the question of how animals should be treated needs to be re-examined. 

D the number of animals demonstrating intelligence is higher than previously thought.

34 In the fourth paragraph, what conclusion does the writer draw about the differing views of experts? 

A Some of them verge on the ridiculous. 

B They are based on flawed evidence. 

C They do not warrant further investigation. 

D A consensus is unlikely ever to be reached.

35 In the fifth paragraph, it is clear that the writer 

A wishes to be seen as objectively reporting Balcombe's experiment. 

B intends to defend Balcombe against a possible criticism. 

C is questioning the details of Balcombe's methods.

D agrees in principle with Balcombe's ideas.

36 What is said in the final paragraph about Balcombe's views?

A They have been directly influenced by research from a previous era. 

B They are shared by an eminent authority on the subject. 

C They have been rejected as extreme by one opponent. 

D They are seen as objectionable in some quarters.