Seals are fin-footed, semi-aquatic mammals that spend significant portions of their lives both in water and on land. These diverse creatures, including true seals (phocids) and eared seals (otariids), are adapted for marine environments but regularly come ashore. This ability to transition between aquatic and terrestrial habitats is crucial for various life processes.
Why Seals Come Ashore
Seals come ashore for several essential activities beyond foraging. They rest and sleep, a behavior known as “hauling out,” which conserves energy. Reproduction is another reason; seals give birth and nurse their young on land.
Molting is another reason seals come ashore. This annual process involves shedding old fur and sometimes skin to grow a new coat. Time on land is necessary because blood flow must be directed to the skin for new hair growth, which is less efficient in cold water. Seals also haul out for thermoregulation, either warming up in the sun or cooling down in the shade or wind. Finally, coming ashore provides refuge from aquatic predators like sharks and orcas.
Factors Affecting Time Out of Water
The duration seals spend out of water varies considerably by species and situation. Different seal species have distinct terrestrial habits; for instance, true seals and eared seals exhibit varying mobility on land, influencing their haul-out patterns. Elephant seals, known for their “catastrophic molt,” can spend weeks ashore for this process, shedding both fur and skin. In contrast, harbor seals may haul out daily for shorter periods, typically between 7 and 12 hours.
The purpose of being ashore is a major determinant of duration. A quick rest might involve only a few hours, while molting or pupping can extend terrestrial stays for days to over a month. Pups and sick or injured seals often spend more time on land; some harbor seal pups remain ashore for up to 48 hours while their mothers forage. Environmental conditions, such as weather, temperature, and tide levels, also influence how long seals stay out of the water. Human presence or other disturbances can cause seals to return to the water prematurely, disrupting their resting and physiological processes.
How Seals Adapt to Land
Seals possess several adaptations that enable their time out of water. A thick layer of blubber provides insulation, helping them regulate body temperature and prevent excessive heat loss or overheating on land. Their fur also contributes to insulation and protects their skin from mechanical damage and UV radiation.
Circulatory adjustments allow seals to regulate blood flow to their skin, which is crucial for temperature control, especially during molting when increased circulation to the skin is needed. While not as agile as on land, true seals move by undulating their bodies in a caterpillar-like motion, sometimes called “galumphing,” using their strong abdominal muscles for propulsion. Eared seals, however, can rotate their hind flippers forward, allowing them to “walk” more effectively on all fours.
Encountering Seals on Land
When encountering seals on a beach or coastline, it is important to observe them responsibly and maintain a safe distance. Seals often appear to be resting and are typically not in distress. Keeping at least 50 to 100 yards (about half a football field) away protects both the animal and yourself.
Disturbing seals can cause them stress, interrupt resting periods, and even lead to mothers separating from their pups. Never feed seals, as this can make them dependent on humans and cause health issues. If a seal appears sick, injured, or entangled, contact local wildlife authorities or rescue organizations.