From sifting through topsoil for native truffles to cracking open hard shells of seeds and nuts to munch on the tasty kernels, Australia bettongs and potoroos are described as 'ecosystem engineers' in a two-way relationship between their rich diet and environmental health. However, with native ecosystems and potoroid marsupial numbers in decline, ecology and evolution experts are working to understand how difficult it is to bite into the foods these leading foragers seek out.