Mammalian sperm thermotaxis is driven by modulation in flagellar beating patterns.

Thermotaxis, the ability to navigate temperature gradients to reach high or low-temperature regions, has long been reported to be one of the mechanisms which steer sperm inside the reproductive tract. Despite the clear importance of understanding how temperature affects sperm motility and how sperm navigates temperature gradients, little is known about this process. In this paper, we develop a microfluidics assay to study bovine sperm thermotaxis in detail. Furthermore, we investigate how sperm flagellar beating is affected by the temperature of the surrounding environment. Through this analysis, we are able to report a novel behaviour previously unreported for mammalian sperm cells. We support our investigation with numerical simulations which help us conclude how the the temperature-dependent flagellar beating patterns and the resulting spermatozoa dynamics lead to sperm thermotaxis.