Review: Sperm: Comparative morphology and function related to altered reproductive strategies and fertility in mammals

ABSTRACT Reproduction and development are fascinating processes that exhibit significant differences among mammals. Successful propagation of species depends on male fertility and the ability of the sperm to fertilize and activate the egg and support early development. Remarkably, the specifics of how sperm structure and function have evolved and their crucial roles in fertility remain largely unknown. This synthesis provides a concise review of comparative anatomy and physiology of mammalian sperm structure and how inevitable changes regulate fertility.