Do animals experience grief? It depends what we mean by the word. Certainly, many mammals and even birds clearly exhibit symptoms of what has been termed "separation distress" when they are parted from a mate, a parent or their offspring.
Research on the subject has tended to focus on the young of higher mammals such as primates but according to a leading expert on grief, John Archer, there is sufficient evidence from other types of relationship and other species "to suppose that the reactions are widespread in those social animals that form relationships based on individuality."
Professor Archer, a professor of psychology at the University of Central Lancashire, explains in his book The Nature Of Grief: "In other words, grief will occur in species where there are prolonged relationships involving individual recognition, based on parental care, kinship or mutual benefit."
Where humans may differ from animals is in the ability to recognise death for what it is. For at least 60,000 years, we have seen dead bodies as immediately distinct from the living and we treat them in a distinct way, by quickly giving them burial. But some primates have been observed carrying their dead infants around with them for periods after their decease.
Jane Goodall, the expert on chimpanzees, saw mother chimpanzees carrying dead babies on more than one occasion, for up to a day, while the distinguished American naturalist George Schaller once saw a gorilla mother carry its dead infant for four days before finally abandoning the decaying corpse.
Professor Archer writes that "studies of the mental processes of other animals ... indicate that the conceptual level necessary for understanding death has not been achieved."
However, he says, loss is something they do understand. "There is ... abundant evidence that reactions essentially similar to those shown by humans occur in social animals which have lost or been separated from a social companion with whom they have an evolutionarily important relationship."