Are you ready to embark on a journey to the frozen North, where one of the most enchanting creatures on the planet resides? Meet the harp seal – a captivating and stunning mammal that has fascinated people for centuries. In this article, we will uncover some of the most interesting and mesmerizing facts about these species, revealing the secrets of their enchanting world.
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Phocidae
Genus: Pagophilus
1. They have different appearances throughout life
Harp seals, or Greenland seals, belong to the family of true seals and share the characteristic features of this group, such as short flippers and the absence of external ear flaps. Their front flippers are equipped with sturdy, thick claws, whereas the claws on their back flippers are comparatively smaller and narrower.
These seals have a size of about 5 – 6 feet (1.5 – 1.8 m) in length and weigh around 260 – 300 pounds (118 – 136 kg), with the females being smaller than the males. The seals have a sturdy physique, a small, flattened head with a small snout, and 16 teeth in their lower and upper jaws.
What makes these creatures different from other seal species is their unique coat. The adult harp seals have a black face and are light gray in color with a curved black patch on their back resembling a harp or a saddle. This is why these seal species are called harp seals or saddleback seals. Some individuals also have dark blotches dispersed across their whole body.
However, harp seals are not born with this coat color. The pups are born with a yellow coat that gradually turns white before their first molt. Their young and most females come in a silver-grey color with black dots. Only mature males and a few females develop the iconic black harp markings on their body.
2. Habitat
Harp seals are typically found in the coastal ocean waters adjacent to pack ice. These creatures favor areas with rough ice at least 0.25 meters thick. Since they rely on pack ice for reproduction, their range is limited to areas where pack ice forms seasonally.
There are 3 primary populations of harp seals: the largest being in the Northwest Atlantic Ocean, with others residing in eastern Greenland and the Barents Sea. You can find these animals in some countries like the US, Canada, Ice land, Russia, Greenland, Norway, and Svalbard Jan Mayen.
3. They are born to live in the cold waters
Due to their habitat in the North Atlantic and Arctic Oceans, these cute Arctic seals have developed various adaptations for survival in the cold climate.
Harp seals, similar to most marine mammals, possess a thick layer of fat known as blubber beneath their skin. This blubber acts as insulation and energy storage. It keeps the seals warm and supplies energy during times of fasting or food deprivation. Additionally, blubber streamlines their body, making them swim more efficiently.
Besides blubber, these species also contain brown fat, also known as brown adipose tissue. This form of fat helps to warm up blood returning from the body surface and acts as a food reserve, particularly in newly-weaned pups, providing them with energy.
The seals’ flippers function as heat exchangers to regulate their body temperature. They squeeze their rear flippers together and their front flippers against their bodies to minimize heat loss when on ice. Additionally, to prevent heat loss, their bodies can also reroute blood flow from the periphery.
Their big eyes are designed to help the harp seals see both underwater and above the surface. These eyes contain a tapetum lucidum that enhances their visual acuity in low-light environments, and their pupils are mobile, allowing them to handle the bright glare of the Arctic ice.
Similar to camels, Arctic seal animals have a protective membrane covering their eyes that shields them from salty seawater when they are submerged. Their eyes are also safeguarded from harm by the lubrication from the lacrimal glands.
Furthermore, their whiskers, or vibrissae, are extremely sensitive to vibration. These provide the animal with a tactile sense on land as well as the ability to detect movement underwater.
4. Harp seals are part-time loners
Harp seals typically prefer being alone. However, during the breeding and molting season, they become extremely sociable and form enormous groups of thousands of members. Even within these large colonies, there are smaller groups with their own hierarchies.
Not only do these seals gather in big groups in the mating season, but they also do this when feeding and traveling in migration season. They frequently travel far from their pack ice habitat during the summer and return northward when the Arctic regions are once again covered in thick ice.
The whitecoat seals often embark on roundtrips of over 3,100 miles (5000 km) every year, traveling with other harp seals. Throughout their migration, they brave the open ocean waters.
The migratory behavior of these seals is determined by the locations where they breed and undergo molting. During the winter, they breed at the southern boundary of their habitat range. In the spring, they begin their molting process in the adjacent area. Once their molting is complete, they move towards the northern boundary of their habitat range to stay for summer and eat. When then September comes, they come back to the breeding grounds.
Communication in harp seals involves a diverse range of vocal tones. The pups typically use a sound known as ‘bawling’ to communicate with their mothers, while ‘mumbling’ is commonly observed during playtime. Adults use growls to warn off possible dangers. They can make over 19 distinct vocal calls for courting and mating purposes while underwater.
5. They’re skillful swimmers
As sea mammals, harp seals spend the majority of their lives at sea. That’s why they are skilled swimmers. They are commonly observed swimming in the cold waters of the North Atlantic and Arctic oceans.
They also have remarkable diving abilities. These species can dive up to depths of roughly 885 feet (270 meters) and remain submerged for up to 15 minutes. While on land, their movement resembles that of a caterpillar.
(Despite their adorable, fluffy appearance, it’s crucial to note that harp seals can be quite aggressive towards humans and their bites have the potential to cause infections.
6. They eat almost everything
Harp seals are carnivorous and excellent hunters who would hunt everything and are not choosy about their diet. They can consume nearly any prey that comes their way, including fish, crustaceans, and invertebrates.
Scientists found out that these seals eat up to 70 different types of invertebrates (krills, amphipods) and 67 different types of fish (Arctic cod (or Polar cod), gadiform fish, Greenland halibut, Capelin fish, herring, American plaice, and flatfish). Their diet is frequently affected by their place and the season.
On average, a harp seal eats between 2 to 6 kg of food each day, with the amount varying determined on their life stage. For instance, a pregnant female seal can feed on 9 kg of food a day. On the other hand, during the molting phase, both females and males tend to eat less.
Typically, harp seals hunt in the coastal waters, though occasionally they venture into deeper waters. To look for food, they dive to depths of 150-200 meters. During this, their nostrils slits shut, making them unable to smell. To hunt prey, they instead rely on their vibrissae or whiskers to detect vibrations created by prey movements.
Hap seals have quite a few predators. Their young are preyed upon by polar bears, wolves, and foxes, while the adults face danger from Greenland sharks and orcas.
7. Reproduction
Every year from February to April, mature harp seals go back to the mating sites in Newfoundland, the White Sea, and the Greenland Sea. Male seals establish their dominance and compete for mating rights by fighting with teeth and flippers.
To attract females, the males perform various courtship behaviors such as blowing bubbles, vocalizations, underwater displays, and flipper movements. If the female is attracted, they will mate underwater. Dominant males can mate with multiple females. Once mating is finished, females gather in groups before giving birth.
The female will go through an 11.5 – months gestation period. She gives birth on sea ice and does it in as short as 15 seconds. She usually gives birth to one pup. If the pack ice is unavailable, females can postpone the implantation of fertilized eggs into the womb for about 3 months, delaying birth.
A newborn harp seal has a size of 3 feet (90 cm) in length and weighs around 25 pounds (11 kg). As mentioned before, the cute pup at birth lacks blubber and has yellow fur from amniotic fluid. However, this coat will soon turn pure white, helping the seal to absorb sunlight and keep it warm.
For up to 12 days after birth, the mother nurses her pup exclusively. During this period, the female does not hunt and can lose up to 6.6 pounds (3 kg) of weight per day, while the pup gains approximately 5 pounds (2.5 kg) daily.
The milk of the mother begins at 25% fat, which grows up to 40% near weaning. This high-fat milk allows the pup to grow rapidly and develop a thick layer of blubber.
After feeding offspring for 12 days, the seal mother abandons her pup and prepares to mate. At this stage, the pup weighs around 80 pounds (36 kg) and starts growing a grey coat underneath its white fur.
The arctic seal pups remain on the ice for approximately 6-7 weeks without food, relying on their internal energy sources to keep warm. During this time, they can lose up to 50% of their weight and become vulnerable to predators, particularly polar bears as the ice melts. Sadly, as many as 30% of pups cannot make it to their first birthday.
When the juvenile loses its white coat, it’s time to learn some lessons about hunting and swimming. It will go through several moltings before becoming an adult. Females reach sexual maturity at the age of 4 – 7 years old while the males are later, about 7 – 8 years.
The harp seal lifespan is quite long. They can live about 30 years.
8. Threats
Currently, the conservation status of harp seals is classified as “Least Concern,” with a population of approximately 7.6 million as of 2019. However, their population is gradually declining, and experts fear that they may soon become classified as “Vulnerable”.
Human activities pose a significant threat to harp seals. Hundreds of thousands of snow seal animals are hunted each year for fur, omega-3 fat, and meat. These species are also threatened by other threats, such as fishing gear, polluted water, oil spills, vessel collisions, or energy exploration.
The oil spill is one of the most dangerous risks that creatures can be exposed to. When a harp seal comes into contact with oil, its fur loses its ability to repel water, making it challenging for the seal to swim, stay afloat, and maintain body warmth. Additionally, oil ingestion or inhalation can harm its reproductive, respiratory, central nervous, and digestive systems, as well as irritate or burn its skin.
Climate change is also a main threat. Harp seals depend on sea ice to give birth, nurse offspring, and molt. Global warming leads to melting ice, depriving the seals of their necessary habitat for all those activities above.
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