The use of chemical and energy-intensive delignification processes in industrial pulp production produces cellulose fibers that are hydrophilic, hygroscopic and functionally restricted to paper and cardboard applications. Here we propose a bio-based alternative to chemical digestion, in which herbivores are used to harvest and grind lignocellulosic materials, followed by natural fungal growth to delignify and hybridize to create hierarchical composite papers with altered, water-repellent surface properties. These papers include cellulosic and fungal biopolymers made by cultivating T. versicolor and P. ostreatus on elephant dung. Papers with significantly more hydrophobic surfaces were obtained with glucosamine contents of only 0.1% by weight. The tensile strengths and moduli of elasticity of the paper were improved with longer fungal growth periods of several weeks, resulting in a comprehensive interface of cellulose microfibrils through robust nanoscale fungal chitin-β-glucan networks within the papers. Papers made from lignocellulosic material that had been colonized with P. ostreatus for 16 weeks showed the highest tensile strengths and more hydrophobic surfaces than T. versicolor. The hybridization of lignocellulose with fungal biopolymers, which leads to improved surface and mechanical properties, underlines the expanded possibilities of fungal delignification bioprocessing and demonstrates the considerable potential of fungal biorefinery as an economical and as yet underutilized technology.