Here are some interesting facts about moles that I bet you didn't know:

1) Moles are not rodents. They belong to the mammalian Order Soricomorpha which is the same as shrews and hedgehogs.
2) Their primary food source is earthworms.
3) Moles create two different tunnel systems. The subsurface runways and the deep runways.
4) Moles can create up to 100ft of tunneling in a day.
5) A typical "infestation" of moles is only 1-3 moles per acre of land.

As you can see, it doesn't take a lot of moles to create a lot of damage. Their constant tunneling wreaks havoc on lawns. Often, once the problem moles have been eliminate you will find new moles that have taken over that once occupied territory.