Seals frequently come ashore in a behavior known as “hauling out,” which is a temporary break from their aquatic life. This amphibious habit allows them to fulfill important physiological and social needs. Hauling out is a normal part of a seal’s life cycle and is not typically a sign of distress or injury. Observing a seal on a beach or rock is usually a sighting of an animal engaged in essential rest and recovery.
Seasonal Biological Drivers
The most consistent and mandatory reasons seals haul out are driven by their annual reproductive and integumentary cycles. Pupping season requires females to come ashore to give birth and nurse their young, a period where they must remain on land for weeks until their pups are weaned. The specific timing of this reproductive haul-out varies significantly; for example, Harbor seals generally give birth in the late spring or early summer, while other species may pup in the winter months.
Following pupping season, seals undergo an annual molt, shedding old fur and skin. This process necessitates extended time out of the water because new hair growth requires increased blood flow to the skin. Being on land raises the seal’s skin temperature, accelerating the molt and preventing excessive heat loss. Harbor seals show their highest haul-out numbers during the summer molting period, typically between late July and mid-August.
Daily Patterns and Environmental Influences
Apart from these yearly cycles, seals haul out on a daily basis primarily for rest and thermoregulation. Seals are endotherms, and they regulate their body temperature by using the shore to either warm up or cool down, depending on the air temperature and wind speed. On warmer, calmer days, many seal populations exhibit a diurnal pattern, peaking in haul-out activity around midday or early afternoon to benefit from the sun’s warmth.
Tidal state is another major influence, as many seals prefer to rest on sites that are only exposed during low tide. The lower water level maximizes the available dry resting space, providing a safer and more isolated area away from aquatic predators. However, if a haul-out site is on a man-made structure or a high rock, the influence of the tide may be less pronounced. Seals may also adjust their daily patterns to avoid human disturbance, sometimes shifting to nocturnal haul-outs during the busy summer months.
Observing Seals Safely
When seals come ashore, the public must maintain a safe distance, as federal law strictly prohibits the harassment or disturbance of these protected marine mammals. Observers should stay at least 50 yards (about 150 feet) away from resting seals to avoid altering the animal’s natural behavior.
If a seal raises its flippers, yawns repeatedly, or flees into the water, it is a clear sign of stress, indicating you are too close. Mother seals with pups require an even greater distance, as human presence can cause the mother to abandon her young. If an animal appears visibly injured or entangled, contact local stranding networks rather than attempting to intervene.