Collected in the 1970s, he spent several years working with the US Navy divers. With their keen directional hearing, these animals were also trained to detect various objects in the ocean, and mark them for recovery. An adult grey seal may live more than 40 years, however, a more typical life expectancy is 35 years for females and 30 years for males. The life expectancy for harbor seals is only slightly lower. Unlike their name, grey seals exhibit a variety of colors and patterns.
Females are typically light in color, with brown or black spots or patches.
Males have a dark coat with light spots. However, immature grey seals may have similar coloration as adult harbor seals, which have light rings on their dark coats. Neptune, a 26-year old male grey seal weighs approximately 450 lbs. Seals can swim up to 25 mph. However, many will travel at an average cruising speed of 12 mph.