Non-flying mammals (i.e. all mammals except bats) have been found to feed on the nectar of several species of plant. This is known as therophily. Though some of these mammals are pollinators, others do not carry or transfer enough pollen to be considered pollinators. The group of non-flying pollinators is composed of marsupials, lemurs, rodents, shrews, and elephant shrews. As of 1997 studies have documented non-flying mammal pollination involving at least 59 species of mammal distributed among 19 families and six orders. As of 1997, there were 85 species of plants from 43 genera and 19 families which were visited by these mammals. In many cases, a plant species is visited by a range of mammals. Two examples of multiple mammal pollination are the genus "Quararibea" which is visited by twelve species and "Combretum" which is visited by eight (although not all these animals actually pollinate the flowers).