Durant, as a pokemon, is thirty centimeters tall. It is known to make nests with other durant, like ants do. Just how large are these nests?
Their jaws are most similar to the Argentine Ant, so they will be considered just exceptionally large. Said Argentine ants can fit in holes as small as 1 mm by 1 mm, so Durant are 300 times as large in both height and width. It can be assumed that length is increased similarly, so 300 times 2.4 mm (average worker length) is 720, or 72 centimeters.
Argentine ants, however, aren't known to dig deep nests, as they are too weak, and thus live under light leafage on the ground, or under small rocks. This is in contrast to Durant, who burrow and make nests in mountains.
Entry holes must be at least a foot wide and tall, just to fit a Durant. We can then look towards another inspiration, the genus Polyrhachis, whom dig extensive soil nests. Extending these statistics to Durant can tell us that they might well colonize entire mountains as their own.