In every field of war in the history of humankind, regardless of the era or the cause, battlefields have been littered with the bodies of soldiers and their animal companions.
Animal 'soldiers', both two- and four-legged have made extraordinary contributions to conflicts across the globe and are now acknowledged and remembered in their own right alongside their human counterparts.
While Simpson's donkey Murphy, who was posthumously awarded the RSPCA's Purple Cross, is always rightly remembered as one of Australia's great heroes, countless other animals have served their country as well.
The war horse is often considered the archetypal symbol of animals in battle with more than 130,000 horses shipped from Australian ports during the First World War alone, to serve in Australian and allied forces overseas.
Only one of these horses returned to Australian shores.
Sandy the Waler belonged to Major General William Bridges, who died at Gallipoli.
After Bridges' death, Sandy served in Egypt and France until, after months in an English quarantine station, he finally returned home to Australia by sea, landing in Melbourne in 1918.
He lived out his days in peace and quiet at Maribyrnong and died in 1923.
The rest of his kind sadly, either died in the field or were humanely destroyed, unable to return to Australia with their riders.
Horses and camels served as mounts and for transportation, donkeys and mules were used as beasts of burden, hauling weaponry and strategic artillery from one point to another as well as much-needed supplies for troops.
In the second great global conflict, a battle of a different kind was taking place in the skies over Europe.
While Spitfires fought Messerschmitts carrier pigeons were evading German-trained peregrine falcons trying to stop them delivering their information.
These pigeons saving countless lives and earned 31 Dicken Medals for bravery.
And dogs too have formed an essential part of military strategy - carrying communications, facing incredible dangers as "para-dogs" during World War One, and in perhaps their most enduring role, as trackers, exposing the enemy and their weapons.
Eleven dogs served with the Australian army in Vietnam between 1967 and 1970, but despite their immense involvement, lengthy tours of duty and countless lives saved, none of the 11 returned to Australia.
These dogs are not alone in their contribution to the Australian Defence Forces, with many serving in conflicts including Korea, Malaya, Borneo, Somalia, Bougainville, East Timor and Afghanistan.
Nor should the role of animals as mascots and pets during conflict be underestimated - they provided valuable relief from the stresses of service life and a small sense of normality in uncertain conditions.
They have trodden same path to war as their human counterparts with almost every battalion or ship having an animal companion.
They appear to be inexorably drawn to each other seeking comfort, a reminder of home or a distraction from the devastation and fear around them.
Many mascots have been credited with saving their mates' lives through superior senses (like hearing) detecting incoming aircraft long before the humans in the camp.
Navy cats accompanied ships for hundreds of years and were considered good luck charms.
Not only did they boost morale and bring a touch of normality to shipboard life, they also performed an essential function, keeping the rodent population at bay, protecting the ship's food stores and the health of the sailors on board.
The role of animals in conflict is now recognised on a designated day in Australia, February 24, and in 2009 the Australian War Memorial in Canberra unveiled a sculpture which commemorates the service animals past and present have given.
You can read more about Digger's amazing story at www.awm.gov.au/collection/C1246162