Graminivore

In zoology, a graminivore (not to be confused with a granivore) is an herbivorous animal that feeds primarily on grass^[1] (specifically "true" grasses, plants of the family Poaceae). The word is derived from Latin graminis, meaning "grass", and vorare, meaning "to eat."^[2] Graminivory is a form of grazing.

Horses, cattle, capybara, hippopotamuses, grasshoppers, geese, and giant pandas are examples of graminivores. Some carnivores, such as dogs and cats, are known to eat grass occasionally.

• 
  Red kangaroo eating grass
• 
  Horses also eat grass
• 
  A capybara grazing at Hattiesburg Zoo

References

Look up graminivore in Wiktionary, the free dictionary.