Study Subjects at Play (IMAGE) Washington University in St. Louis Caption Two young raccoons visiting a feeding tray for breakfast are unwitting participants in a study to see whether they will give up available food in order to avoid being parasitized by ticks. Credit Fritzsche Usage Restrictions please credit 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.