About moles
Moles are subterranean creatures, meaning they spend all of their time below ground. What is left behind and seen are the raised up tunnels just below the surface that they create when digging through the yard, or sometimes mounds of dirt as they excavate areas below the surface.
They are insectivores, and feed mostly on earthworms and grubs, but will eat any insect that they can fit in their mouths. They have extremely high metabolisms, forcing them to eat nearly their weight in food each day. Their tunnels do major damage to grass because they are carving through it tearing up roots, not eating them as other rodents do (voles).
Moles are solitary creatures except during breeding season, so yard damage is typically from no more than a few moles. They do not live in colonies like some others rodents do. Contrary to popular belief, grub killers are not truly effective deterrents, because they do not target earthworms.
Even effective grub control does not always work to keep them away. Moles can be trapped effectively if done right, and combining that with deterrents that also target earthworms is the most effective solution to getting moles out and keeping them away.