<P> Seed dispersal via ingestion by vertebrate animals (mostly birds and mammals), or endozoochory, is the dispersal mechanism for most tree species . Endozoochory is generally a coevolved mutualistic relationship in which a plant surrounds seeds with an edible, nutritious fruit as a good food for animals that consume it . Birds and mammals are the most important seed dispersers, but a wide variety of other animals, including turtles and fish, can transport viable seeds . The exact percentage of tree species dispersed by endozoochory varies between habitats, but can range to over 90% in some tropical rainforests . Seed dispersal by animals in tropical rainforests has received much attention, and this interaction is considered an important force shaping the ecology and evolution of vertebrate and tree populations . In the tropics, large animal seed dispersers (such as tapirs, chimpanzees and hornbills) may disperse large seeds with few other seed dispersal agents . The extinction of these large frugivores from poaching and habitat loss may have negative effects on the tree populations that depend on them for seed dispersal . A variation of endozoochory is regurgitation rather than all the way through the digestive track . </P> <P> Seed dispersal by ants (myrmecochory) is a dispersal mechanism of many shrubs of the southern hemisphere or understorey herbs of the northern hemisphere . Seeds of myrmecochorous plants have a lipid - rich attachment called the elaiosome, which attracts ants . Ants carry such seeds into their colonies, feed the elaiosome to their larvae and discard the otherwise intact seed in an underground chamber . Myrmecochory is thus a coevolved mutualistic relationship between plants and seed - disperser ants . Myrmecochory has independently evolved at least 100 times in flowering plants and is estimated to be present in at least 11 000 species, but likely up to 23 000 or 9% of all species of flowering plants . Myrmecochorous plants are most frequent in the fynbos vegetation of the Cape Floristic Region of South Africa, the kwongan vegetation and other dry habitat types of Australia, dry forests and grasslands of the Mediterranean region and northern temperate forests of western Eurasia and eastern North America, where up to 30--40% of understorey herbs are myrmecochorous . </P> <P> Seed predators, which include many rodents (such as squirrels) and some birds (such as jays) may also disperse seeds by hoarding the seeds in hidden caches . The seeds in caches are usually well - protected from other seed predators and if left uneaten will grow into new plants . In addition, rodents may also disperse seeds via seed spitting due to the presence of secondary metabolites in ripe fruits . Finally, seeds may be secondarily dispersed from seeds deposited by primary animal dispersers, a process known as diplochory . For example, dung beetles are known to disperse seeds from clumps of feces in the process of collecting dung to feed their larvae . </P> <P> Other types of zoochory are chiropterochory (by bats), malacochory (by molluscs, mainly terrestrial snails), ornithochory (by birds) and saurochory (by non-bird sauropsids). Zoochory can occur in more than one phase, for example through diploendozoochory, where a primary disperser (an animal that ate a seed) along with the seeds it is carrying is eaten by a predator that then carries the seed further before depositing it . </P>

Explain the various modes of dispersal of seeds