Unlike kangaroos and eucalyptus - eating possums , koalas are hindgut fermenters .
Hindgut fermenters ' ' digestive retention can last for up to 100 hours in the wild , or up to 200 hours in captivity .
Unlike kangaroos and eucalyptus - eating possums , koalas are hindgut fermenters , and their digestive retention can last for up to 100 hours in the wild , or up to 200 hours in captivity .