Several per acre. Unlike their cousins the shrews, moles are almost blind. They use their sense of smell and the ability to feel vibrations to find food and navigate.
Gardeners blame moles for ruining plants.
But they don't actually eat plant roots or bulbs. Instead, they're hungry for earthworms and insect larvae. Moles help control populations of harmful insects. Digging is hard work. So an active mole must eat about half its entire body weight each day.