Instead , many other herbivores ( foregut fermenters such as kangaroos and small hindgut fermenters such as rabbits , voles and possums ) have digestive systems that sacrifice maximal fibre digestibility for a capacity to process large amounts of forage , even when forage fibre content becomes very high .
BIOLOGIST : In a bush that doesn \'t have predator control , every hectare of indigenous forests within New Zealand has between2 and6 ship rats and about3 to13 possums .
