Cuttlebone signifies a special class of ultra-lightweight cellular natural material possessing unique chemical, mechanical and structural properties, which have drawn considerable attention in the literature. The aim of this paper is to better understand the mechanical and biological roles of cuttlebone. First, the existing literature concerning the characterisation and potential applications inspired by this remarkable biomaterial is critiqued. Second, the finite element-based homogenisation method is used to verify that morphological variations within individual cuttlebone samples have minimal impact on the effective mechanical properties. This finding agrees with existing literature, which suggests that cuttlebone strength is dictated by the cuttlefish habitation depth. Subsequently, this homogenisation approach is further developed to characterise the effective mechanical bulk modulus and biofluidic permeability that cuttlebone provides, thereby quantifying its mechanical and transporting functionalities to inspire bionic design of structures and materials for more extensive applications. Finally, a brief rationale for the need to design a biomimetic material inspired by the cuttlebone microstructure is provided, based on the preceding investigation.