What is a ruminant?

To ruminate means to chew something over and over again.

Many mammals, such as humans, cannot eat grass and plants, but herbivorous animals can eat grass.

A ruminant is also a herbivore–a herbivorous animal. A ruminant is a hoofed mammal that feeds on plants. A ruminant has a special four-chambered stomach that can digest and ferment plant-based food.

A ruminant uses its teeth to grind their plant food into balls, which are stored in the stomach and can be regurgitated later. Re-chewing is also called regurgitation. A ruminant re-chews its food ball, which is also called the bolus, or cud.

A ruminant includes cattle (cows and bulls), goats, sheep, giraffes, yaks, deer, antelope, and kangaroos.

A ruminant has a four-chambered stomach. The four compartments, or chambers, include: (1) rumen, (2) reticulum, (3) omasum, and (4) abomasum.

The four-chambered stomach enables a ruminant to chew and chew and chew, by regurgitating their plant food mixed with saliva. Each time the animal chews, it absorbs nutrients, called cellulose and hemi-cellulose, in the plant fibre.

A ruminant produces a lot of saliva. It is estimated that cows produce 100-150 litres of saliva a day as they chew grass. Saliva has acids that help to digest the plant fibre.

A ruminant also produces a lot of gas – they fart a lot. The gas is called methane gas.

Some ruminants, such as hippopotamuses, have three-chambered stomachs, and can also chew their cud.

Horses, rabbits, and rhinoceroses are herbivores that eat plants, but they are not ruminants because they have a one-chambered stomach. They are called monogastric animals – one stomach animals.

 

Photographer: Martina Nicolls

Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM