The increasing evidence of the commonality of genetics and biochemistry of all species suggests that the conventional thinking of a universe centred on only one species which is sharply divided from all other forms of life is an outdated relic, yet the scientific taboo of sentimentality and anthropomorphism means that important questions about our commonality with other species are often ignored.
One intriguing topic is that of friendship and loyalty in animals, both between unrelated individuals of one species, and between individuals of different species.
Observations of social species such as primates, dogs, dolphins, hyenas, bats and elephants show that there can be close, durable relationships between unrelated individuals who seek out each other's company; help, protect and support each other and show signs of depression on the death or disappearance of the friend. Elephants show recognition of individual friends even after decades of separation.
Recent observations of other less intelligent species also indicate that individuals may have a preference for certain companions. A study of 133 black tipped reef sharks showed that individual sharks persistently associated with selected individuals and persistently avoided others, proximity and territory could not explain the riddle of their companionship. Such studies indicate that bonds between unrelated individuals may occur in a whole range of species.
The theory of reciprocal altruism is often given as the basis for animal friendships (and is probably the rationale for many human ones too) but loyalty to companions may bring danger as well as benefits, for example it is believed that mass stranding of pilot whales is often the result of the pod following and refusing to desert an individual in distress.
Cross species bonds are even more puzzling. It is difficult to observe such relationships between animal species in the wild. Humans who have been in frequent contact with wild species may develop associations with individuals and the foundation of animal domestication must have been the bond that developed between individual humans and those of other species.
Unlikely interspecies friendships such as Albert the sheep and Temba the orphan elephant at Shamwari Game Reserve seem exceptional, but it is common practice to provide lonely, stressed, and anxious animals with companions of other species. The famous racehorse Seabiscuit had an old horse, a dog and a spider monkey as lifelong companions.
Certainly many of us who share our lives with other species regard them as friends. As we approach ANZAC Day it seems appropriate to acknowledge the many animals who have played a part in human conflicts. The role of the war horse is now mercifully redundant, but dogs not only actively serve in modern warfare but are now also used to provide therapy for human war veterans who are disabled or suffering PTSD. While scientists may describe these animals as conditioned creatures without emotions, I tend to think that their human military companions probably regard them quite differently.