What are ruminants?

The grass-eating animals that have a rumen to partially digest food and form cud are known as ruminants. 

The grass that ruminants feed on is rich in cellulose which is a type of carbohydrate. 

Horses and Rabbits have a sac-like structure known as the Caecum present between the oesophagus and the small intestine. 

It helps in the digestion of cellulose.