Centaurs

Centaurs have a humanoid torso and equine body. However, their internal organs are arranged differently. Their Humanoid torso contains extra-large heat and lungs compared to humans. This helps them meet greater oxygen demand. Their esophagus runs through their torso and into their equine body.

Their spine, muscles and ligaments are extra flexible around the transition point between humanoid and equine. This gives a wide range of motion. Allowing them to bend and absorb impact forces resulting from striking while running, with either fists or weapons.

There is a gene that controls hair growth and other factors above and below the transition point. The reason for and origin of this transition point is unknown.

The equine body contains the digestive, excretory, and reproductive systems. The digestive organs are larger than compared to horse, able to process more food to meet a greater caloric demand.

Their ribs in the equine body are not used for breathing but provide structure, along with some protection for a developing fetus in a pregnant female. Prior to labour, the fetus's head and torso tend to sit closer to the ribs.

Female centaurs have two sets of mammary glands that coincide with the two development stages of a centaur infant. The stages are known as the carry stage and the mobile stage. Centaurs are born with more developed brains than human babies but less developed than horses. In the carry stage, they need to be carried around by their mother while they develop the ability to walk. During this phase, they feed from the humanoid breasts on the torso. Once they enter the mobile stage, they can walk independently and feed from equine teats as they develop their speech and fine motor skills.