Last week a vast bronze sculpture was unveiled in Montrose, on the east coast of Scotland, by Prince Andrew. It depicts a hero of the second world war, wearing a seaman's cap, who was decorated with "the equivalent of the George Cross". It's a bit late, perhaps, but otherwise unsurprising - until I tell you that the hero was a dog. The statue depicts a St Bernard called Bamse, which reputedly rescued two Norwegian sailors. It is the latest manifestation of the new Cult of the Heroic Animal.

The Imperial War Museum in London is currently running an exhibition called The Animals' War. It features stuffed mascots, tales of the "desperate plight" of 200 animals trapped by the fighting in Iraq, and photos of dogs wearing gas masks. It tells us about the "PDSA Dickin medal - the animals' Victoria Cross", which has been awarded to 23 dogs, 32 pigeons, three horses and one cat for "acts of conspicuous gallantry and devotion to duty in wartime". The museum resounds with cries of "aaah!" and "how sweet!". War is now cute.

Last year Disney released an animation called Valiant about the heroics of a group of messenger pigeons in the second world war. In 2004 a vast sculpture called Animals at War was unveiled by Princess Anne on Park Lane in London. It cost £1.5m and is dedicated "to all the animals that served and died alongside British and allied forces in wars and campaigns throughout time ... From the pigeon to the elephant, they all played a vital role in every region of the world in the cause of human freedom. Their contribution must never be forgotten." In Liverpool there are now two statues commemorating a dog - Jet - that was used to find victims of air raids in the second world war.

I have no objection to remembering the suffering of animals. If someone started a subscription for a statue of a battery pig or a broiler chicken (conveniently forgotten by almost everyone), I might even contribute. But the emphasis given to animals' suffering in war highlights a failure to acknowledge the suffering of human beings. The tableau in Park Lane carries the justifying motto: "They had no choice." Nor did the civilians killed in Iraq, the millions of women raped over the centuries by soldiers, or the colonial subjects who died of famine or disease in British concentration camps. You would scour this country in vain for a monument to any of them.

Bamse has been dead for 62 years. Both the Park Lane memorial and the exhibition at the Imperial War Museum were inspired by a book by Jilly Cooper - the patron saint of English bourgeois sentiment - called Animals in War. But it was first published in 1983. It is only since the invasion of Iraq that this Disneyfication of war seems to have become a major industry.

Animals have featured in war memorials for at least 4,000 years. But they have, for the most part, been used as representations of human dominance and courage. The tableau in Park Lane, depicting a weary shire horse, two exhausted pack mules and an Irish setter seeking his master, could almost be a response to Landseer's insouciant lions in Trafalgar Square. If these beasts were conceived, like his, with anthropomorphic intent, they would represent the mute, trudging foot soldiers of the imperial army, prey to Trafalgar Square's top predators. The inscription might have read: "What passing-bells for these who die as cattle?" But they weren't. No metaphor is intended here; we are asked to concentrate on the suffering of the animals, not the infantry.

The monument has an interesting list of sponsors. Alongside the RSPCA, Battersea Dogs' Home, the Household Cavalry and the Amalgamation of Racing Pigeons is an odd collection of industrialists. There's Sir Anthony Bamford, who runs JCB and who was exposed a few days ago as the president of the Midlands Industrial Council (MIC), which has donated almost £1m to the Conservative party. The Labour party accuses the MIC of exploiting a loophole in electoral laws, which oblige donors to reveal their identity. There's Lord Ballyedmond, who - both directly and through his company Norbrook Laboratories - gave £1.1m to the Tories in 2001. They are joined by the PR company Spa Way (best known for representing the "private security contractor" Tim Spicer); the late property developer and former Conservative councillor Sir Stanley Clarke; and Eva and Kirsten Rausing, the niece and daughter-in-law of the Swedish industrialist Hans Rausing, whose tax affairs have caused some controversy here and who has donated £343,000 to the Conservative party.

Perhaps the most interesting name on the list is William S Farish III. An old friend of the Bush family, he is a major donor to the Republican party and was the US ambassador to Britain from 2001 to 2004. One of his tasks here was justifying the war with Iraq. He inherited much of his money from his grandfather, the Texan oil millionaire William S Farish II.

In 1942 William S Farish II pleaded "no contest" to charges of criminal conspiracy with the Nazis, and was denounced by Senator Harry Truman for behaviour that "approaches treason". Through the Standard Oil Company of New Jersey, of which he was president, he was alleged to have run a cartel with the German company IG Farben. Farben manufactured Zyklon B, the poison used in the gas chambers, and ran a plant using slave labour at Auschwitz. Among other deals, William S Farish II had agreed to share patents for making synthetic gasoline and artificial rubber with Farben, while withholding them from the US navy. He was fined and died soon afterwards. His son died a few weeks later in an air accident, leaving the family fortune to William S Farish III.

So what is going on? What is so appealing about these memorials to the members of the royal family who agreed to unveil them, to the crowds who have packed the new exhibition, and to the rightwing multimillionaires who financed the giant tableau? Why, when the war we started in Iraq appears to have killed hundreds of thousands of human beings, have we become obsessed by the non-human victims of conflict?

I'm not sure, but the last panel in the Imperial War Museum's exhibition offers a possible explanation. It reproduces the inscription on a monument erected by the British in Port Elizabeth, South Africa, raised to commemorate "the animals that died in the Anglo-Boer War, 1899-1902". This was a war of almost unprecedented brutality in which the British beat the Boers by burning down their homes and herding them into the world's first large-scale concentration camps, where more than 40,000 people died. "The greatness of a nation," the inscription says, "consists not so much in the number of its people or the extent of its territory, as in the extent and justice of its compassion."

This is a worthy index, on which Britain would have been placed close to the bottom, unless we were judged by our compassion - or sentiment - for animals. These monuments, perhaps, permit us to see ourselves as kind people, even as unspeakable acts are committed on our behalf.

· George Monbiot's latest book is Heat: How to Stop the Planet Burning, monbiot.com