Throughout human history, people have fought in wars - and they have taken animals with them. But what did these animal war heroes do? And how are they honoured on Remembrance Day?

How long have humans used animals in war? Humans have enlisted animals to help fight their wars since prehistoric times, and some of the world's earliest historical sources tell of battles between ancient warlords in horse-drawn chariots. Dogs and horses were probably the first animals used in war. Many are still used today in modern military and police tasks.

What other animals have served? Throughout history, humans have not just used horses and dogs in battle. The Ancient Greeks and Romans catapulted bee hives into besieged cities. At the battle of Tondibi in West Africa in 1591, armies used stampeding cattle against lines of soldiers.

In the Early Modern period across East Asia and the Indian Subcontinent, armies even trained elephants for war. Though their use declined with the spread of firearms, they continued to be used in combat in Thailand and Vietnam into the 19th century.

Animals have also helped soldiers in practical ways. During World War One, troops enlisted cats and dogs to hunt rats in the trenches, while canariesThe small birds are much more sensitive to small amounts of gas than humans. Before gas warfare, they were used in mines to check for carbon monoxide. were used to detect poisonous gas. Animals also served as mascots, with bears, pigs and cats among those known to keep troops company.

Why are pigeons useful? Like many birds, pigeons have an innatePresent naturally. homingAn animal with a homing ability can return to its territory after travelling away from it for a length of time. ability. It is thought to be based on their sensitivity to the direction of the Earth's magnetic field. Many birds use the skill in their annual migrations.

People have used this skill to send messages since at least the 6th century BC. The Persian king, Cyrus, used pigeons to communicate with distant parts of his empire. Generals have used them during war for centuries. The use of carrier pigeons reached its peak during World War I, when more than 200,000 birds were used by the Allied ForcesThe major Allied powers in World War One were Great Britain (and the British Empire), France and the Russian Empire, formally linked by the Treaty of London in September 1914. alone.

What is the Dickin Medal? Commonly referred to as the "Animal Victoria CrossThe highest medal of honour. It is given for valour in the face of the enemy to members of the British Armed Forces.", the medal was instituted in 1943 to honour the work of animals in World War Two The words on the medal read "For gallantryAnother word for courage, especially in battles." and "We also serve".

The first three recipients were three pigeons serving with the RAFThe Royal Air Force is the UK's air force.. The medal was awarded 54 times during World War Two to 32 pigeons, three horses, 18 dogs and one cat called Simon. The most recent animal to win the medal is Treo, a black Labrador who served as an arms and explosives search dog in Afghanistan.

Were animals always looked after? There are certainly countless stories of close bonds forged between humans and animals. There was the friendship of Warrior and Captain Seely, who fought side by side throughout World War One. There was the HMS Glasgow sailor who risked his life to save an enemy's pig from drowning.

Sadly, though, not all animals could survive. The RSPCAThe Royal Society for the Prevention of Cruelty to Animals. estimates that more than 480,000 horses, mules and camels died between 1914 and 1918 alone. Every year on Remembrance Day, millions around the world wear a poppy to honour those killed in war. Many choose a purple poppy specifically to remember the animals.

How do we still use animals for military operations? Today, military and police dogs are seen all over the world and undertake numerous tasks including support work, search and rescue and detection.

Other animals are used too. Bottlenose dolphins and sea lions have been trained by the US Navy to perform military tasks, like harbour protection or mine clearance. And in September, an African giant pouched ratA species of nocturnal rat. They can be trained to detect a certain compound within explosives, meaning that they can find mines much quicker than traditional metal detectors. won a prize for discovering 39 landmines and 28 unexploded bombs while working in Cambodia.