Description: A sleek, streamlined, fusiform body. Coloration is gray to gray-green or gray-brown on the back, fading to white on the belly, lower jaw, and anal regions. The belly may be pinkish. These colors are a type of camouflage known as countershading. When viewed from above the dark back surface blends with the dark depths. When viewed from below, the lighter colors blend with the bright surface of the sea. Bottlenose dolphins live in groups called pods. Dolphins in a pod appear to establish strong social bonds. Behavioral studies suggest that certain animals prefer association with each other and recognize each other after periods of separation. Field observations suggest that mother-calf bonds are long-lasting. Though bottlenose dolphins have lived as long as 48 years their average life expectancy is around 20 years.