No, horses are not ruminants. Ruminants are a group of mammals that have a specialized stomach with four compartments that allow them to digest fibrous plant material, such as grass and hay, through a process called rumination. The four compartments of their stomach include the rumen, reticulum, omasum, and abomasum.

Horses, on the other hand, have a simple stomach with only one compartment. However, they have a unique digestive system that is adapted to break down and digest fibrous plant material. Their large intestine includes a fermentation chamber, called the cecum, where fiber is broken down by bacteria and other microorganisms. This process allows horses to extract nutrients from the fibrous plant material and convert it into energy that they can use for their daily activities.

While horses are not ruminants, their digestive system is still highly specialized for the digestion of fibrous plant material, and they require a diet that is high in roughage, such as hay and grass, to maintain their health and wellbeing.