Terrestrial ungulates are for the most part herbivores, with some of them being grazers. Trampling grazers kill seedling trees but not grasses. Bison are nomadic grazers and travel in herds. Snail and nudibranch species are two common grazers of epiphytes. Herds of buffalo mow down grasses and make way for more selective grazers. Grasslands allow for more grazers, such as horses, rhinoceroses, and hippos. Antelope are important to their habitats as grazers and browsers. Grazers as well as browsers, the chital mainly feed on grasses throughout the year. African elephants are mostly browsers while Asian elephants are mainly grazers. Geese and dabbling ducks are primarily grazers. They are generalist feeders, and both grazers and browsers. They are generalist feeders, and are both grazers and browsers. The grazers are then preyed on by predatory species. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. Dexter cattle are very hardy, efficient grazers and are able to thrive on poor land.