<p>Mammalian sperm develop in testis and mature in epididymis, although they are functionally incomplete. After sperm are ejaculated, they are capacitated in an oviduct. Capacitated sperm are functionally a final condition and are able to bind to an oocyte. During capacitation, sperm motility changes from “activation” to “hyperactivation” [Yanagimachi 1994]. Activation is a progressive motility and symmetric flagellar movement. In contrast, hyperactivation is a specialized motility and asymmetric flagellar movement. Additionally, hyperactivation allows sperm to pass through an envelope of the oocyte. In several studies [Alasmari et al., 2013; Sugiyama et al., 2019], it has been reported that ability of hyperactivation is correlated to IVF success. Therefore, in order to examine sperm fertile ability, measuring hyperactivation is important.</p><p>There are two methods to examine sperm motility. One is a manual method which analyzes movies recorded by a video-microscopy. Another is an automatic method which used computer-aided sperm analysis (CASA). Since sperm motility pattern depends on animal species [Yanagimachi 1994], there are no method that all animal sperm are able to be analyzed. In the presentation, I talk about merits and demerits of a manual method and an automatic method in a sperm motility assay.</p><p>Yanagimachi R. (1994) The Physiology of Reproduction Vol 1: 189–317.</p><p>Alasmari W. et al., (2013) Hum Reprod 28: 866–876.</p><p>Sugiyama Y. et al., (2019) J Reprod Dev 65: 541–550.</p>