Mammoths were herbivores, which means they only ate plants. What kind of plants mammoths ate depended on the species of mammoth and what habitat they lived in. Some mammoths only ate grasses but other mammoths could also eat shrubs, leaves, and bark. Mammoths used their specialized teeth to grind and eat their food. Their tusks could have been used to eat food by scraping ice and snow off vegetation.
Similar to their elephant cousins, it is thought that Mammoths spent most of their time eating. A 6-ton woolly mammoth would need to eat about 90kg of food a day!