10 Incredible Harp Seal Facts

Pagophilus groenlandicus is better known as the harp seal, Saddleback Seal, or Greenland Seal. Native to the Atlantic and the Arctic Oceans, harp seals are earless (true) seals of the family Phocidae and the most abundant pinnipeds in the Northern Hemisphere. Mature harp seals measure anywhere from 5 feet, 7 inches to 6 feet, and 7 inches long and weigh between 254 and 309 pounds. Here is a list of 10 harp seal facts that explore what makes these semiaquatic mammals so engaging. 

10. Harp Seals Are Quite Sociable

For our first foray into harp seal facts, we’ll examine how harp seals interact with one another. Harp seals spend most of their lives at sea swimming, hunting, or migrating between feeding and breeding grounds. While they occasionally travel and feed alone, by nature, they are gregarious and social animals that enjoy the company of other seals.

You can usually find harp seals traveling in small groups or hanging out together on ice floes. Within these small groups, harp seals form distinct hierarchies, with each member falling into place according to their status. During the breeding season, harp seals come together to create large colonies that can contain several thousand seals. 

9. Harp Seals Get Their Name from Their Distinctive Markings

Like many animals, the harp seal gets its name both from its physical characteristics and geographic distribution. Its scientific name, Pagophilus groenlandicus, translates to “ice-lover from Greenland” in Greek. Meanwhile, its common names—harp seal and Saddleback Seal—refer to its distinctive markings.

Mature harp seals have silver-gray fur and often feature black harp-shaped markings on their dorsal side, hence their name. Occasionally, these markings create a dark, saddle-like shape on the back and sides, which is why people sometimes refer to them as Saddleback Seals. Whether you think these markings look like a harp or saddle, the name harp seal predominates. 

8. Some Harp Seals Migrate Long Distances

Next up, we have one of our most extraordinary harp seal facts that concerns their amazing migratory instincts. Like many marine mammals, harp seals migrate long distances every year. Outside the breeding season, some groups travel up to 3,100 miles to their feeding grounds before making the long trip back to their breeding colony. 

Harp seals possess excellent navigational instincts and can effectively find their way back to their colonies with a high degree of accuracy. That said, harp seals sometimes wander outside their normal range that extends from Scandinavia to northeastern Canada. Harp seals have been sighted as far south as Great Britain and North Carolina, although these sightings happen only occasionally.

7. Harp Seals Are Excellent Swimmers

As previously mentioned, harp seals spend most of their time at sea and only venture on land to rest or breed. It’s, therefore, no surprise that harp seals have evolved as exceptional swimmers. 

Compared to other true seals, they only dive to moderately deep depths. They tend to spend most of their time at depths of only 50 to 150 meters but will sometimes dive up to 500 meters below the surface. Dive depths are usually more shallow in the spring and summer and tend to increase in the fall and winter. Harp seals average around 8 dives per hour and can hold their breath for over 20 minutes. They are extremely agile swimmers and can efficiently catch all manner of sea creatures during their dives. 

6. Harp Seals Rely Heavily on Their Blubber

One of the most well-known harp seal facts concerns how harp seals rely on their blubber to survive. Like all seals, harp seals are protected by a thick layer of fat known as blubber. This blubber surrounds their core but not their flippers, which instead evolved circulatory adaptations to prevent heat loss. 

Harp seals rely on their blubber to keep them warm and insulate their bodies from the cold temperatures in the water and on land. During lean times when food is scarce or they cannot hunt, harp seals also rely on their blubber to provide them with energy. Additionally, their blubber makes them more streamlined in the water, thereby improving their agility and speed. 

5. Harp Seals Make a Wide Range of Vocal Sounds

Like other seals, harp seals employ a wide range of vocal sounds that they use to communicate with one another. Most communication occurs underwater, with scientists recording over 19 unique vocalizations underwater to communicate with one another. The most typical calls are used to attract mates or to coordinate actions between members of the same group. 

Harp seals emit a wide variety of sounds including clicks, growls, trills, and whistles. They vary their sounds in pitch, frequency, and volume in order to avoid masking one another. Adults will often growl or warble to warn off predators. Males typically emit calls to signal their territory to potential rivals, while pups will “yell” to signal their mothers or “mumble” when playing with other pups. 

4. Female Harp Seals Give Birth on Ice Floes

Unlike some other mammals, harp seals are quite promiscuous and rarely breed in monogamous pairs. Courtship and breeding almost always occur underwater, with males engaging in displays involving blowing bubbles, vocalizations, and paw movements to attract females. 

Female harp seals gestate their young for around 11.5 months and move onto ice floes shortly before giving birth. They only give birth on the ice, as it provides a safe place for them to nurse their pups. Births happen very quickly, with some lasting as short as 15 seconds. 

3. Harp Seal Pups Are Born with White Fur

Next, we have one of our cutest and most recognizable harp seal facts. At birth, newborn harp seals weigh around 25 pounds and measure about 3 feet long. Harp seal mothers feed their pups milk for approximately 12 days, during which time the mothers can lose up to 6.6 pounds in weight per day. 

Harp seal pups are born with long, almost pure white fur. Their white fur helps them to absorb sunlight and warm themselves, as they are born with very little fat. They can gain up to 4 pounds per day by drinking their mother’s high-fat milk. Once they reach about 3 to 4 weeks old, they shed their white fur for their juvenile coat. They molt again at around 13 to 14 months old, which is when they begin to develop a spotted harp shape on their backs. 

2. Harp Seals Are Opportunistic Carnivores

Be it seals, sea lions, or walruses, all pinnipeds are carnivorous, and harp seals are no exception. Harp seals live on a diverse diet of sea creatures that includes dozens of different species of fish and invertebrates. Although they prefer to eat certain prey, they tend to feed opportunistically on whatever food they can catch at the time. 

Krill makes up a large part of harp seals’ diet. They also eat a large variety of fish, including capelin, herring, flatfish, and cod. Harp seals do not chew their food. Instead, they swallow it whole or bite off pieces that they then swallow in chunks. They will also crush the shells of crustaceans using their powerful teeth before scarfing down the soft flesh inside. 

1. Some People Hunt Harp Seals

For our final entry on our list of harp seal facts, we’ll explore how humans interact with harp seals. Currently, harp seals continue to be hunted by a select number of fishing populations in Canada, Russia, Norway, and Greenland. In the past few decades, these hunts have come under increasing scrutiny due to claims of inhumane and cruel tactics. 

Seal hunters typically target young seals less than 1-year-old and kill as many as 30,000 harp seals each year. The seals are typically hunted for their pelts, which are used in the fur and oil industries. Hunters normally kill harp seals using a traditional club known as a hakapik but will also sometimes shoot seals from boats. Despite these annual culls, most countries limit the number of harp seals that may be hunted, and the IUCN currently lists harp seals as a species of Least Concern. 

The photo featured at the top of this post is © iStock.com/slowmotiongli