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.
Seals have strong senses of hearing, sight, touch and smell.
Their directional hearing underwater allows them to locate prey and other seals through vibrations in the water. Additional vibrations are detected by the vibrissae - whiskers on the seals' nose that are connected to nerve fibers under the skin, which allows the seals to detect the movement of prey items in murky water. The seals' large eyes permit them to see well both above and below the water. Seals have a large number of photoreceptor cells in their eyes that aid them in seeing in murky water. In addition, their pupils expand to let in more light in dark or murky conditions and contract to thin slits in bright light.