Until recently, humans were thought to be the only species to experience complex emotions and have a sense of morality.

But Prof Marc Bekoff, an ecologist at University of Colorado, Boulder, believes that morals are “hard-wired” into the brains of all mammals and provide the “social glue” that allow often aggressive and competitive animals to live together in groups.

He has compiled evidence from around the world that shows how different species of animals appear to have an innate sense of fairness, display empathy and help other animals that are in distress.

Prof Bekoff, who presents his case in a new book Wild Justice, said: “The belief that humans have morality and animals don’t is a long-standing assumption, but there is a growing amount of evidence that is showing us that this simply cannot be the case.”

WOLVES

Wolves live in tight-knit social groups that are regulated by strict rules. If a pack grows too large, members are not able to bond closely enough and the pack disintegrates. Wolves also demonstrate fairness.

During play, dominant wolves will “handicap” themselves by engaging in role reversal with lower ranking wolves, showing submission and allowing them to bite, provided it is not too hard.

Prof Bekoff argues that without a moral code governing their actions, this kind of behaviour would not be possible. If an animal bites too hard, it will initiate a “play bow” to ask forgiveness before play resumes.

ELEPHANTS

Elephants are intensely sociable and emotional animals. Research by Iain Douglas Hamilton, from the department of zoology at Oxford University, suggests elephants experience compassion and has found evidence of elephants helping injured or ill members of their herd.

In one case, a Matriarch known as Eleanor fell ill and a female in the herd gently tried to help Eleanor back to her feet, staying with her before she died.

In 2003, a herd of 11 elephants rescued antelope who were being held inside an enclosure in KwaZula-Natal, South Africa. The matriarch unfastened all of the metal latches holding the gates closed and swung the entrance open allowing the antelope to escape.

This is thought to be a rare example of animals showing empathy for members of another species—a trait previously thought to be the exclusive preserve of mankind.

DIANA MONKEYS

A laboratory experiment trained Diana monkeys to insert a token into a slot to obtain food. A male who had grown to be adept at the task was found to be helping the oldest female who had not been able to learn how to insert the token. On three occasions the male monkey picked up tokens she dropped and inserted them into the slot and allowed her to have the food.

As there was no benefit for the male monkey, Prof Bekoff argues that this is a clear example of an animal’s actions being driven by some internal moral compass.

CHIMPANZEES

Known to be among the most cognitively advanced of the great apes and our closest cousin, it is perhaps not surprising that scientists should suggest they live by moral codes.

A chimpanzee known as Knuckles—from the Centre for Great Apes in Florida—is the only known captive chimpanzee to suffer from cerebral palsy, which leaves him physically and mentally handicapped.

Scientists have found that other chimpanzees in his group treat him differently and he is rarely subjected to intimidating displays of aggression from older males.

Chimpanzees also demonstrate a sense of justice and those who deviate from the code of conduct of a group are set upon by other members as punishment.

BATS

Vampire bats need to drink blood every night but it is common for some not to find any food. Those who are successful in foraging for blood will share their meal with bats who are not successful.

They are more likely to share with bats who had previously shared with them. Prof Bekoff believes this reciprocity is a result of a sense of affiliation that binds groups of animals together.