The enormous diversity of non-human biota is a specific challenge when developing and applying dosimetric models for assessing exposures to flora and fauna from environmental radioactivity. Dosimetric models, adopted by the International Commission on Radiological Protection (ICRP), provide dose conversion coefficients for a large variety of biota, including the Reference Animals and Plants. The models use a number of simplified approaches, often ignoring presumably insignificant details. Simple body shapes with uniform composition and density, homogeneous internal contamination, a limited set of external radiation sources for terrestrial animals and plants, and truncation of radioactive decay chains are a few examples of simplifying assumptions underlying the dose conversion coefficients included in ICRP Publication 108. However, many specific assessment tasks require dosimetric data for non-standard species or irradiation scenarios. The further development of dosimetric models aims at the implementation of flexible choices of animals and plants, as well as of their irradiation conditions (e.g. trees); more systematic consideration of internal exposures from radionuclides concentrated in specific organs; and task-oriented choice of decay chains based on ICRP Publication 107. An extensive set of non-human dosimetric data might require specific software to facilitate fast, accurate, and flexible selection of pertinent dose conversion coefficients for specific assessment tasks.