From Mountain Birth to Mammalian Marvels: A Review of the Himalayas' Role in Mammalian Biogeography

ABSTRACT Background The Himalayas emerged from a semi‐aquatic landscape into the tallest mountain system on Earth, driving major environmental changes. Yet, how mammalian communities responded to this transition remains poorly understood. Addressing this gap is critical for understanding the resilience of mammalian assemblages under ongoing environmental changes. Aim We summarize the history of the Himalayas, highlighting key landscape and environmental transformations, and use mammals to exemplify the Himalayas' role in community assembly. Findings Our review highlights that initial uplift due to the northward movement of the Indian Plate towards the Eurasian Plate resulted in a shallow sea and surrounding semi‐aquatic environments, supporting earliest ancestors of modern cetaceans. As uplift progressed, it served as a biological corridor between two plates, facilitating mammalian dispersal in both directions, with subsequent radiations. Continued uplift gave rise to differential climate zones, establishing diverse mammalian communities across elevational gradients. With further increase, it transitioned into a significant biogeographic barrier, driving desertification to the north, intensifying monsoon systems in the south, and shaping river systems and valleys, all impacting the biogeographic complexity of the region. During Quaternary glaciations, river valleys acted as climatic refugia, enabling the persistence of many mammalian lineages. Throughout, precipitation remained higher in the Eastern Himalayas than in the west, leading to additional longitudinal variation in mammalian assemblages. Today, Himalayan mammals span multiple biogeographic realms, with strongest mammalian community similarities to Southeast Asia. Future Direction Much of the material presented reflects evidence from the fossil record, spatial mapping, and recent but sparse genomic work on megafauna, which alone cannot fully explain mammalian responses to changes in the Himalayas. Modern genomic studies and broader sampling, mainly of highly diverse but underrepresented small taxa (rodents, bats, and shrews) are needed to update species origins, diversification, and community assembly to advance knowledge on Himalayan biodiversity dynamics.