Which of the following is not a ruminant?

The correct answer is that a pig is not a ruminant. Ruminants are animals that have a specialized stomach structure that allows them to digest plant-based food through a unique fermentation process. These animals typically have a four-chambered stomach that includes the rumen, reticulum, omasum, and abomasum, enabling them to break down fibrous plant materials effectively.

Cows, sheep, and deer all belong to this category and exhibit behaviors adapted to their ruminant anatomy, such as regurgitating and re-chewing their food, commonly known as "cud." They primarily eat grasses and other coarse plant materials, which require this additional digestive process for proper nutrient absorption.

Pigs, on the other hand, are classified as monogastric animals. They have a single-chambered stomach, which processes food differently. Their digestive system is designed to handle a more varied diet that can include grains, fruits, vegetables, and animal products, but it does not involve the rumination process seen in ruminants. Understanding the differences between these animal classifications is important for livestock management and nutrition practices.