This study is designed to find an answer to the question, “How to get solutions to provide energy efficiency in building shells inspired by nature?” Methodologically, the chapter focuses on animal skins/shells within organisms that have adapted to the environment and have developed specific abilities to interact and cooperate with changing environmental conditions in different climates. The principles in animal skin/shells have been investigated in two stages to understand how building shell/envelope/a façade in architecture can be designed to adapt to the environment. The first stage is investigating and defining the strategies and adaptation mechanisms found in animals living in different climatic zones, then identifying the ideas having architectural potentials and solutions that can be transferred to the building envelopes. The results obtained in the light of five examples show that bio-inspired/bio-informed surfaces have the potentials to obtain effective results in building shells to be utilized in different climatic zones. Finally, it is seen that energy-efficient façade systems can be designed according to biomimetic approaches with innovative and sustainable solutions based on thermal, light, air, and water regulation.