One of the main advantages of horses in war is their speed and maneuverability, and they're better at that than elephants or camels for instance. Besides that, they're smaller, and so require less food to maintain, which could be a good thing in long campaigns.
Almost everywhere.
Horses were widely used in America's Revolutionary War. Dogs and birds were other animals that were also utilized for the war effort.
Horses were commonly used.
Donkeys Horses Pidgoens and Tracker Dogs
Dogs, pigeons, horses, glow worms, elephants, parrots, oxen, pigs, cats, donkeys and camels were all used in world war 1.
Cats , dogs , horses and carrier pigeons .
Horses and mules can be used as draft animals (i.e. to pull loads).
Many animals such as horses, ponies, and donkeys were used for transport of military equipment, food, and so on. Horses were used by Mounted Infantry and Cavalry but, as the Western Front was usually static, they were not often used. Dogs were also used for various purposes.
Dogs to track/ guard I believe, but definitely horses for fighting on their backs. There is also a great story about a dog used in the civil war as a spy, see the added link.
When there was no other food, and they were starving, soldiers have eaten horses and mules that were military animals.
No horses are used for "war horses" anymore.
Yes. Horses, goats, mules, war dogs, messenger pigeons, etc. all have been used in war. And any animal that gets in the way (Buffalo, tigers, elephants, etc.) become casualties too.