A war elephant is an elephant that is trained and guided by humans for combat.
The war elephant's main use was to charge the enemy, breaking their ranks and instilling terror. Elephantry are military units with elephant-mounted troops. They were first employed in India, the practice spreading out across south-east Asia and westwards into the Mediterranean. Their most famous use in the West was by the Greek King Pyrrhus of Epirus and in significant numbers by the armies of Carthage, including briefly by Hannibal.
In the Mediterranean, improved tactics reduced the value of the elephant in battle, while their availability in the wild also decreased. In the east, where supplies of animals were greater and the terrain ideal, it was the advent of the cannon that finally concluded the use of the combat elephant at the end of the 19th century, thereafter restricting their use to engineering and labour roles.
The first elephant species to be tamed was the Asian elephant, for use in agriculture. Elephant taming – not full domestication, as they are still captured in the wild, rather than being bred in captivity – may have begun in any of three different places. The oldest evidence comes from the Indus Valley Civilization, around roughly 4500 BC. Archaeological evidence for the presence of wild elephants in the Yellow River valley during the Shang Dynasty (1600–1100 BC) of China may suggest that they also used elephants in warfare. The wild elephant populations of Mesopotamia and China declined quickly because of deforestation and human population growth: by c. 850 BC the Mesopotamian elephants were extinct, and by c. 500 BC the Chinese elephants were seriously reduced in numbers and limited to areas well south of the Yellow River.