Compared to a predator’s diet, plant food has two great advantages: it is abundant and it does not run away. ‘Herbivorous mammals’ explains how these advantages are matched by difficulties: plants are generally of low nutritional value and must be eaten in large amounts; leaves with protective abrasive particles can quickly wear down herbivores’ chewing teeth; and mammals cannot make their own cellulase enzymes for breaking down cellulose to sugars. The eating habits and the challenges of small herbivores (e.g. rodents, rabbits, and hyraxes) are considered, as well as those of large ungulates and elephants; marsupial herbivores (e.g. kangaroos, wombats, and koalas); and specialist herbivores (pandas, dugongs, and manatees).