megaherbivore 

Any very large herbivore that weighs more than 1000kg.

"Elephants are classified as megaherbivores and consume up to 150 kg of plant matter per day."

megaherbivore by CToad7 March 10, 2023

megaherbivorous 

Relating to a megaherbivore

"The Indian elephant has a megaherbivorous diet; it consumes 150kg of plant matter each day."

megaherbivorous by CToad7 March 10, 2023