Seals on land look really miserable! They have tear drops trickling down their cheeks. But the tears are not related to emotional state of the seal in any way! As in most of the aquatic creatures, the seal produces the tears to lubricate their eyes. They are non-migratory animals which spend their lives close to the shore, rarely venturing more than a few miles out to sea, but can also be found in rivers.
Are seals friendly? Seals are very intelligent creatures, and, as mammals, they do form social attachments. Females are smaller than males, growing to an average length of 4. Like other true seals, harbor seals do not have external ears and cannot use their hind flippers to move on land. Harbor seals are have long been considered non-migratory and tend to stay close to home, but telemetry data have shown they sometimes travel 62 to miles from their tagging location.
They haul out to molt, give birth, raise their pups, bask in sunlight and avoid predators. In water, harbor seals are much more graceful. They can spend several days at sea foraging for food and even sleep underwater for up to 30 minutes at a time. Harbor seals hunt in shallow and benthic waters, eating mainly fish, crustaceans, cephalopods and shellfish.
Depending on their location, harbor seals are preyed on by great white sharks , Greenland sharks , orcas , Steller sea lions and walruses. If they avoid predators, harbor seals can live for 30 to 35 years. How do you characterize sounds? Amplitude Intensity Frequency Wavelength How are sounds made?
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During the molting period between spring and fall, depending on geographic location, they are more gregarious, hauling out in large numbers in the same area of beach or reef. When hauled out, they mostly sleep but remain aware of their surroundings and alert to possible dangers. If this space is impinged on, they will become agitated and vocalize by grunting, growling, and snorting. Actual fighting is rare except among males during the mating season.
Harbor seals are graceful and agile swimmers, but are very awkward when on land. Their land movement is similar to that of caterpillars and inchworms. It is accomplished by an undulating movement of the body. In spite of this handicap they can reach a very respectable speed when properly motivated.
Propulsion while swimming is accomplished by a sculling motion of the hind flippers. The fore flippers are used for steering, i. Curious, but wary, harbor seals are constantly alert to perceived dangers and will quickly vacate an area they consider unsafe. Not nearly as social as the sea lion group, they dislike being disturbed, even by their own kind, and most commonly avoid body contact except during the breeding season. Harbor seals are well adapted to their marine lifestyle. A thick layer of blubber aids in temperature control.
Body shape permits ease of movement through the water and limb development to flippers makes for efficient propulsion. They have little if any color vision, but their black and white vision is keen and is better in the water than out. Their whiskers or vibrissae are very sensitive to vibration and water motion and are an important part of sensory input when the animal is swimming in constricted areas or hunting for food.
Harbor seals and other pinnipeds have a material called myoglobin in their muscle tissues that has the ability to store relatively large quantities of oxygen. This aids the animals in deep dives and long periods under water. The myglobin can supply oxygen when other sources are depleted. They have the ability to direct oxygen-rich blood to critical organs where it is most needed.
Harbor seals have a maximum lifespan of 25 to 30 years, while males tend to have shorter lives than females. This may be explained by the stresses placed on the males during the breeding season. This can be due to a variety of factors including illness, predation, maternal abandonment, extreme weather conditions and accidental injuries.
Pups are especially subject to some land-based predators such as foxes, coyotes, bobcats, and even eagles. Both pups and adults may become food for large sharks, killer whales, and in some areas, polar bears. Harbor seals are very sensitive to human encroachment and may be forced to abandon an ideal habitat for one less suitable to their well-being. Along with human pressures come pollution and other types of habitat degradation that can have negative influence on species viability.
There is presently no commercial harvesting of harbor seals, but there is a limited amount of native subsistence hunting. Some commercial fishers object to having seals steal fish from their nets and kill them to avoid loss of their catch. Seals are on occasion accidentally caught in fishnets as bycatch and die by drowning.
The last few decades have seen population adjustments throughout their range from increase to decrease to stable.
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