Rodents

With over 2,000 living species placed in about 30 families, “Rodentia” are by far the largest order of mammals. Some species spend their entire lives above the ground in the canopy of rainforests; others seldom emerge from beneath the ground. Some species are highly aquatic, while others are equally specialized for life in deserts. Many are to some degree omnivorous; others are highly specialized, eating, for example, only a few species of invertebrates or fungi. Despite their morphological and ecological diversity, all rodents share one characteristic: their teeth are highly specialized for gnawing. All rodents have a single pair of upper and a single pair of lower incisors, followed by a gap, followed by one or more molars or premolars.