Turning Behavior of Human Sperm (IMAGE) University of Warwick Caption Turning behavior of human sperm under flow reversal reveals two distinct swimming modes. Thin lines -- individual trajectories, thick lines -- average trajectories. Left and right turners form a "heart" shape. Credit University of Warwick Usage Restrictions In relation to this release only. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.