Harbor Seal

Harbor Seal facts at a glance

How big is a harbor seal?

An adult harbor seal measures 1.8 m long — about 1.0× the height of an average adult person (1.73 m) — and weighs around 100 kg, about 1.4× an average adult’s body weight (70 kg).

What is a group of harbor seals called?

Explore more animal collective nouns and baby animal names .

A true, earless seal

The harbor seal is a true seal, meaning it has no external ear flaps — just small ear openings — and short front flippers. On land it cannot bring its hind flippers under its body, so it moves with a caterpillar-like wriggle. In the water, though, it is a graceful diver, powered by side-to-side strokes of its hind flippers.

Diving and feeding

Harbor seals are carnivores that hunt fish, squid, and crustaceans. They commonly dive for several minutes and can stay underwater for over twenty, slowing their heart rate to save oxygen. Their long, sensitive whiskers detect the water trails left by swimming fish, helping them hunt even in dark or cloudy water.

Pups that swim within hours

Harbor seal mothers give birth to a single pup that can swim and dive almost immediately after birth. Pups nurse on extremely rich milk for around four to six weeks, gaining weight quickly before being weaned. Mothers often leave pups resting on shore while they forage nearby, so a lone pup is usually not abandoned.

Habitat and range

Harbor seals are among the most widespread of all seals, living along temperate and Arctic shorelines on both sides of the North Atlantic and North Pacific. They favor sheltered bays, estuaries, and rocky coasts, where they haul out on rocks, sandbars, and beaches to rest between feeding trips.

Conservation

Harbor seals are listed as Least Concern overall, though some regional populations are declining. Threats include entanglement in fishing gear, pollution, disease outbreaks, and disturbance at haul-out sites. People are advised to keep their distance from resting seals and pups rather than approaching or trying to rescue them.

Did you know? Harbor Seal facts

• The harbor seal is a true (earless) seal found along cool coasts across the Northern Hemisphere.
• No. Harbor seals are true seals with no visible ears that wriggle on land, while sea lions have ear flaps and walk on rotated flippers. Seals are also generally quieter and more solitary.
• Harbor seals are carnivores that feed on fish such as herring and cod, plus squid and crustaceans, locating prey with their highly sensitive whiskers.
• Usually no. Mothers often leave pups ashore while feeding nearby. Keep well back, keep dogs away, and contact a licensed marine mammal rescue group if a pup looks injured or distressed.
• Harbor seals routinely dive for several minutes and can stay underwater for more than twenty by slowing their heart rate and conserving oxygen.
• Conservation: Least Concern (IUCN).

Diet & feeding

Harbor Seal feeds primarily as a carnivore (fish, squid, crustaceans). Harbor seals are among the most widespread of all seals, living along temperate and Arctic shorelines on both sides of the North Atlantic and North Pacific. They favor sheltered bays, estuaries, and rocky coasts, where they haul out on rocks, sandba

Adaptations

• The harbor seal is a true seal, meaning it has no external ear flaps — just small ear openings — and short front flippers. On land it cannot bring its hind flippers under its body, so it moves with a caterpillar-like wriggle. In the water, though, it is a graceful diver, powered by side-to-side strokes of its hind flippers.
• Harbor seals are carnivores that hunt fish, squid, and crustaceans. They commonly dive for several minutes and can stay underwater for over twenty, slowing their heart rate to save oxygen. Their long, sensitive whiskers detect the water trails left by swimming fish, helping them hunt even in dark or cloudy water.

Behaviour & ecology

• The harbor seal is a true seal, meaning it has no external ear flaps — just small ear openings — and short front flippers. On land it cannot bring its hind flippers under its body, so it moves with a caterpillar-like wriggle. In the water, though, it is a graceful diver, powered by side-to-side strokes of its hind flippers.
• Harbor seals are carnivores that hunt fish, squid, and crustaceans. They commonly dive for several minutes and can stay underwater for over twenty, slowing their heart rate to save oxygen. Their long, sensitive whiskers detect the water trails left by swimming fish, helping them hunt even in dark or cloudy water.
• Harbor seal mothers give birth to a single pup that can swim and dive almost immediately after birth. Pups nurse on extremely rich milk for around four to six weeks, gaining weight quickly before being weaned. Mothers often leave pups resting on shore while they forage nearby, so a lone pup is usually not abandoned.

Communication

• Harbor Seal uses scent, posture, and vocal signals to mark territory and coordinate social behaviour.
• Communication intensity often peaks during breeding seasons and territorial disputes.

Habitat & range

Temperate and Arctic coastal waters

Ecological role

Harbor Seal acts as a predator that helps regulate prey populations and maintain balance in temperate and arctic coastal waters.

Conservation status of the Harbor Seal

Sources & references

This guide is compiled and reviewed against established zoological and conservation references. Key sources for the Harbor Seal:

• IUCN Red List of Threatened Species

  Conservation status (Least Concern) reflects the IUCN Red List category for Phoca vitulina.

• iNaturalist — observations & photos

  Search citizen-science observations and community IDs for Phoca vitulina. Useful for range checks and recent sightings — not a substitute for formal Red List status.

• GBIF — occurrence data

  Global Biodiversity Information Facility species search for Phoca vitulina. Explore published occurrence records used in range research.

• IUCN Red List — Phoca vitulina.

  Conservation status (Least Concern) and population trends.

• Animal Diversity Web — Phoca vitulina. University of Michigan Museum of Zoology.

  Life history, morphology, and range.

• Wikipedia — Harbor Seal.

  General taxonomy and overview (cross-check primary sources).

• Global Animal Guide editorial standards

  How we research, source, review, and update every guide for accuracy.