Apes demonstrate a full range of emotions, including grief and empathy, scientists have discovered.

These emotions have been observed in several species of great apes, both in captivity and in the wild, said Barbara King, an anthropologist at the College of William and Mary in the U.S. city of Williamsburg, Virginia.

The emotions of primates have previously been documented in studies that have looked at incidences of grooming, infant gestures, and aggression in males, said King, but this study is different in that it looks at the spontaneous expression of emotions in day-to-day social interactions.

"Darwin argued that emotions are discreet and they're universal," said Ekman.

The emotions of primates, she added, give us new insight into the evolution of our own emotions and the way they relate to human institutions, even religion. "Religion is emotional at its root,

understanding of the emotions of primates is necessary to understanding human culture, religion, and language