MONKEYS and apes have a sense of morality and the rudimentary ability to tell right from wrong, according to new research.

In a series of studies scientists have found that monkeys and apes can make judgments about fairness, offer altruistic help and empathise when a fellow animal is ill or in difficulties. They even appear to have consciences and the ability to remember obligations.

The research implies that morality is not a uniquely human quality and suggests it arose through evolution. That could mean the strength of our consciences is partly determined by our genes.

Such findings are likely to antagonise fundamentalist religious groups. Some believe the ability to form moral judgments is a God-given quality that sets humans apart.

The scientists say, however, that the evidence is clear. “I am not arguing that non-human primates are moral beings but there is enough evidence for the following of social rules to agree that some of the stepping stones towards human morality can be found in other animals,” said Frans de Waal, professor of psychology at Emory University in Georgia in the United States.

In papers at the annual meeting of the American Association for the Advancement of Science (AAAS) this weekend de Waal described experiments on monkeys and apes to see if they understood the idea of fairness.

The animals were asked to perform a set of simple tasks and then rewarded with food or affection. The rewards were varied, seemingly at random. De Waal found the animals had an acute sense of fairness and objected strongly when others were rewarded more than themselves for the same task, often sulking and refusing to take part any further.

Another study looked at altruism in chimps - and found they were often willing to help others even when there was no obvious reward. “Chimpanzees spontaneously help both humans and each other in carefully controlled tests,” said de Waal.

Other researchers, said de Waal, have found the same qualities in capuchin monkeys, which also show “spontaneous prosocial tendencies”, meaning they are keen to share food and other gifts with other monkeys, for the pleasure of giving.

“Everything else being equal, they prefer to reward a companion together with themselves rather than just themselves,” he said. “The research suggests that giving is self-rewarding for monkeys.”

Related research found primates can remember individuals who have done them a favour and will make an effort to repay them.

De Waal, who has written a book called Primates and Philosophers, said morality appeared to have evolved in the same way as organs such as the eye and the heart, through natural selection.

The debate over whether animals can tell right from wrong and make moral choices dates back to Charles Darwin, originator of the theory of evolution.

He suggested that when sexual reproduction first evolved it forced animals to develop codes of behaviour that became built into their genes. In humans these instincts developed into a sense of right and wrong. This fitted with his view that humans were derived from animals - a view fiercely opposed by the church at the time.

The big question now is why, alone among the primates, humans have developed morality to such a high level. It implies that humans were once subjected to some kind of powerful evolutionary pressure to develop a conscience.

Some researchers believe we could owe our consciences to climate change and, in particular, to a period of intense global warming between 50,000 and 800,000 years ago. The proto-humans living in the forests had to adapt to living on hostile open plains, where they would have been easy prey for formidable predators such as big cats.

This would have forced them to devise rules for hunting in groups and sharing food.

Christopher Boehm, director of the Jane Goodall Research Center, part of the University of Southern California’s anthropology department, believes such humans devised codes to stop bigger, stronger males hogging all the food.

“To ensure fair meat distribution, hunting bands had to gang up physically against alpha males,” he said. This theory has been borne out by studies of contemporary hunter-gatherer tribes.

In research released at the AAAS he argued that under such a system those who broke the rules would have been killed, their “amoral” genes lost to posterity. By contrast, those who abided by the rules would have had many more children.

Other studies have confirmed that the strength of a person's conscience depends partly on their genes. Several researchers have shown, for example, that the children of habitual criminals will often become criminals too - even when they have had no contact with their biological parents.

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