Horse

Horses are animals used for navigation and travel across vast terrain, usually in Titan-infested territory outside the Walls. They are mostly used in expeditions, though they can be seen leading carriages inside the walls. Like all other wildlife, except humans, their presence is completely ignored by Titans. People also use them to haul carts; in the Survey Corps case, they are used for quick travel as well as hauling supplies and provisions.

It is considered virtually impossible to escape the grasp of a Titan without a horse outside the walls, excluding the Forest of Giant Trees where 3D Maneuver Gear can be utilized. Their top speed can range from 75 to 80 kilometers an hour, roughly maintaining the speeds of 35 kilometers an hour.

Breeding
They have been specially bred to allow the Survey Corps to outrun Titans while outside the walls. They are capable of running for long distances without complaint, and are not easily frightened by Titans.

After the fall of Wall Maria, humanity lost a considerable amount of it's territory and resources. In an attempt to make ends meet, the government reached out to rural hunting villages in the hopes of turning them into hired horse breeders. In exchange they would need to stop hunting, as the cost of meat had risen considerably.

A testament to their stamina can be seen when Thomas travels by horse for 12 hours, only stopping for a minute to notify citizens along the way, to notify the higher ups of a breach in wall Rose.

Notable Traits
Speed - They have a top speed of 75-80 km/h(47-50 mph). Making them ideal additions to the Survey Corps.

Endurance - They can maintain a constant speed of 35 km/h(22 mph). Due to their staunch legs, they are capable of withstanding the stress of sudden starts, acceleration, and circling. They are also capable of reaching a speed of 20 km/h(12 mph) while pulling a wagon.

Temperament - They're quite docile and don't normally frighten in the presence of Titans. They nearly constant sound of Three Dimensional Maneuver Gear being used so close to the horses also seems to have no effect on them.

Trivia

 * Horses are noted to be extremely expensive, costing about as much as an average citizen's lifetime earnings, as such the Survey Corps are usually the only ones to have them.
 * They're considered, like human soldiers, apart of the Survey Corps. If they die, it's suggested that you bring back as much of it's mane as possible for a burial.