hARBOR SEALS

Now, for the Harbor Seal:

Harbor seals are found in temperate, subarctic, and arctic waters of the North Atlantic and North Pacific oceans. They inhabit shallow areas of estuaries, rivers, and places where sandbars and beaches are uncovered at low tide. They do not do any extensive migrations, but they do travel in search of food/feeding grounds. It is estimated that there are 300,000-500,000 harbor seals in the wild.

Male harbor seals get up to 6 feet long, with weights up to 375 pounds, although most are a bit smaller. Females are smaller, at 5.5 feet long and weights to 330 pounds. They have a rounded, fusiform body, much “chubbier” than the sea lions.

The harbor seals range in color from light gray to silver with dark spots. Some are black or dark gray to brown with white rings.

The limbs are modified into flippers, as with the sea lions. A harbor seal’s foreflippers are short and webbed, unlike the elongated ones of the sea lions. They also contain noticeable claws, unlike those of the sea lions. The harbor seals use the claws for scratching, grooming, and defense. The foreflippers are covered with hair, absent in the sea lions. There are claws and hair on the hind flippers as well. The harbor seals use their hind flippers in a side to side motion to propel themselves through the water, using them as rudders as well. However, on land, they cannot rotate the hind flippers under the body, so that it moves by bouncing in a caterpillar like motion.

The harbor seal has a rounded head with a fairly blunt snout. It lacks external ear flaps, which we can easily see in sea lions. The teeth are similar to those of the sea lions, used mainly for grasping and tearing but not for chewing. The whiskers/vibrissae are located around the upper lip and cheeks.

In all of its senses (hearing, eyesight, touch, and smell), the harbor seals are similar to the sea lions. As with sea lions, it is believed that their taste sense is weak or nonexistent.

The swimming of harbor seals, although different from sea lions in the use of the hindflippers for propulsion instead of the foreflippers, is otherwise similar in that speeds are around 12 mph, but generally cruising at slower speeds.

They live in shallow waters, and hence, they normally do not dive deep, but it is known that they can dive to more than 600 feet. They can stay submerged for up to 30 minutes, but dives usually last no longer than about 3 minutes. The same physiological adaptations for diving occurs in the harbor seal as in the sea lion.

In fact, much of the physiology and biology of the harbor seal mimics those of the sea lion. However, their behavior is different, in that they are usually solitary and rarely interact with each other except for mating. They will haul out (term used to describe the action of seals/sea lions coming out of the water to inhabit a beach) in loosely organized groups (such as the one at Casa Cove in La Jolla), with none of them touching each other.

Since they cannot rotate their hind flippers under their bodies, their haul out places are limited by height and by tides.

They are probably the least vocal of all pinnipeds. They may snort, hiss, growl, or sneeze in air, although their vocalizations are mainly underwater.

They compete with the sea lions for the same/similar food in the same areas. They eat about 5-6% of the body weight daily (10-18 pounds).

The reproductive actions and process is similar to those of the sea lions except that the males do not maintain as large “harems” nor territories. The pups nurse only for 4-6 weeks, instead of the much longer 6-8 months for the sea lions.

The longevity of harbor seals is about the same as that for sea lions, and human interaction is one of the chief causes for concern for their health in the oceans.