Which of the following animals are classified as ruminants?

Ruminants are a specific category of mammals known for their unique digestive system, which includes a specialized four-chambered stomach that aids in the fermentation and breakdown of fibrous plant material. Cattle are the quintessential example of ruminants, as they possess this advanced digestive system featuring the rumen, reticulum, omasum, and abomasum. This allows them to efficiently process grass and other roughage, deriving energy through a process that involves microbial fermentation.

In contrast, horses, pigs, and dogs do not share this ruminant characteristic. Horses, for instance, are classified as non-ruminant herbivores and have a single-chambered stomach. Pigs are omnivores with simple stomachs and do not have the ruminating capabilities. Dogs are carnivorous and also have a single chamber in their stomach, suitable for digesting protein and fat rather than fibrous plants.

Thus, cattle's classification as ruminants is based on their specific anatomical and physiological adaptations that enable them to effectively digest fibrous plant material through a multi-chambered stomach structure.