Most heteromyids live in complex burrows in the deserts and grasslands of western North America . Some species within the Heteromys and Liomys genera are also found in forests and can be found down as far as northern South America . Most heteromyids live in complex burrows within the deserts and grasslands of western North America , though species within the Heteromys and Liomys genera are also found in forests and extend down as far as northern South America .