Common bottlenose dolphins live in groups called pods that typically number about 15 individuals, but group size varies from pairs of dolphins to over 100 or even occasionally over 1000 animals for short periods of time. Their diets consist mainly of eels, squid, shrimp and wide variety of fishes. They do not chew their food, instead swallowing it whole. Dolphin groups often work as a team to harvest schools of fish, though they also hunt individually. Dolphins search for prey primarily using echolocation, which is a form of sonar.