Possible Clues:

• It's actually a rodent
• Burrowing rodent
• Herbivore named for its habitat
• Western rodent that builds underground towns
• Great Plains dweller
• Flexible ape or rigid rodent
• Rodent with plain tail
• Rodent having plain tail
• North American burrowing mammal
• Burrowing rodent with a barking cry (2 words)