Source: http://monsterhunter.wikia.com/wiki/Monoblos

Monoblos are large hard-shelled wyverns that have the ability to dig and travel underground. Monoblos were named for the strong, singular horn protruding from their head, which are held as a prize by many hunters, as are their hearts, which are very rare.

They have a brown, rock-hard texture to their shell. There is a subspecies of Monoblos known as the White Monoblos. These are generally larger in size than their sand colored counterparts and seen as more dangerous by hunters. Ironically, whilst their ear splitting roar is the bane of hunters they are weak to Sonic Bombs while digging through the ground and not in Rage Mode.

While they have no breath attack, their roar is considered a lethal weapon itself. They are also very physically capable, able to fight off hunters with horn-thrusts and tail-swings. Being able to tunnel beneath the sands of the Desert also means they can sneak up on any potential threats.

Monoblos are aggressive, and will attack Hunters on sight. When suitably enraged their crown will become inflamed with red streaks. They are quick to anger, and will move faster and hit harder while enraged.

Monoblos have only been spotted in the Desert, Old Desert, and Dunes regions. They have also been seen inhabiting the arid areas of the Everwood.