Bull sperm (IMAGE) Frontiers Caption Coexistence of individually swimming and clustered sperm. Clustered sperm are labeled with yellow ovals. Scale bar: 50 μm. Credit S Phuyal, SS Suarez, C-K Tung Usage Restrictions Credit must be given to the creator. License CC BY 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.