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Species Profile

Hooded Seal

Cystophora cristata

The seal with a built-in hood.
Agami Photo Agency/Shutterstock.com

Hooded Seal Distribution

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This map shows coastal regions where Hooded Seal are found.

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A hooded seal relaxing on the ice

At a Glance

Wild Species
Diet Piscivore
Activity Cathemeral
Lifespan 30 years
Weight 410 lbs
Status Vulnerable
Did You Know?

Adult males reach ~2.5-2.6 m and ~300 kg; females ~2.0-2.2 m and ~160 kg-strong sexual dimorphism for a true seal.

Scientific Classification

The hooded seal is a large, ice-associated true seal of the North Atlantic and Arctic seas, notable for extreme sexual dimorphism and the male’s inflatable nasal hood used in display and competition.

Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Carnivora
Family
Phocidae
Genus
Cystophora
Species
Cystophora cristata

Distinguishing Features

  • Adult males possess an inflatable nasal hood (and an eversible red nasal sac) used for visual displays
  • True seal (no external ear pinnae); streamlined body with hind flippers not used for walking on land
  • Large size and pronounced sexual dimorphism (males much larger)
  • Pups are born on sea ice and weaned very rapidly compared with many other seals

Physical Measurements

Males and females differ in size

Length
8 ft 10 in (8 ft 2 in – 9 ft 10 in)
6 ft 7 in (5 ft 11 in – 7 ft 3 in)
Weight
772 lbs (661 lbs – 904 lbs)
441 lbs (320 lbs – 661 lbs)
Top Speed
4 mph
Sustained ~2.0 m/s (7.2 km/h)

Appearance

Primary Colors
Secondary Colors
Skin Type Phocid (true/earless seal): short, dense fur over thick blubber; lacks external ear pinnae; streamlined skin/fur for cold-water foraging and ice-associated hauling out (North Atlantic/Arctic sea-ice breeding).
Distinctive Features
  • Large, ice-associated North Atlantic/Arctic true seal; adult size commonly reported as ~2.0-2.6 m total length (females smaller, males larger).
  • Male hooded seals have a big inflatable nasal hood (nose sac) they blow up in displays; they can also push out a red nasal membrane called the 'red balloon' from one nostril during fights or mating.
  • Phocidae (earless) locomotion traits: no external ear pinnae; hind flippers cannot rotate forward under the body for walking-on ice they move by undulating/contracting the body rather than the sea-lion-like gait of Otariidae.
  • Head appears broad with large dark eyes; prominent mystacial vibrissae (whiskers) used for prey detection in cold, often dim waters.
  • Pelage contrast: bluish-gray 'blue' background with irregular dark spotting in adults; pups are 'bluebacks' (bluish coat) rather than the whitecoats typical of several other northern phocids.
  • Hooded seal females have pups on drifting pack ice. They nurse for only 3–5 days (often about 4). Pups are suddenly weaned and fast on ice while learning to dive.
  • Hooded Seal (Cystophora cristata) in cold North Atlantic and Arctic waters mainly eats fish and squid, dives mid-water/mesopelagic and sometimes very deep (to ~1,000 m) for tens of minutes.
  • Distinct seasonal molt: adults haul out to molt (often on ice) after breeding; coat appearance and contrast can change markedly before/after molt.
  • Typical maximum longevity reported for the species is on the order of ~30-35 years in the wild (compiled life-history summaries in major marine mammal references, e.g., Reeves et al., 1992; later regional assessments).

Sexual Dimorphism

Strong sexual dimorphism: adult males are substantially larger and possess the unique inflatable nasal hood used in display/competition on ice; females are smaller and lack the fully developed hood. Dimorphism is among the most extreme in true seals.

  • Larger body: commonly cited adult male length ~2.5-2.6 m (and often heavier; many references summarize males typically ~300-400+ kg depending on season/condition).
  • Inflatable nasal hood (enlarged nasal sac) that can be expanded over the muzzle/forehead during threat and mating displays; may also produce an everted reddish nasal membrane ('red balloon') as a visual signal.
  • More robust head/neck profile and generally heavier forequarters; facial region often appears darker when hood tissue is distended.
  • Smaller body: commonly cited adult female length ~2.0-2.2 m (and lighter; often summarized ~145-300 kg depending on season/condition).
  • No fully developed inflatable hood; facial profile typically smoother/less bulbous than adult males.
  • Overall more gracile head/neck silhouette compared with adult males.

Did You Know?

Adult males reach ~2.5-2.6 m and ~300 kg; females ~2.0-2.2 m and ~160 kg-strong sexual dimorphism for a true seal.

Pups are nursed for only ~4 days (among the shortest lactation periods of any mammal), then abruptly weaned and left to fend for themselves.

Hooded seal milk is extremely energy-rich (often reported around ~60% fat), supporting rapid pup growth in just a few days.

Males can inflate a black nasal hood over the snout; during intense displays they can also evert a red nasal membrane ("balloon") from one nostril.

Satellite-tag studies report very deep dives-documented to ~1,000 m (order of 10^3 m) and long submergences (tens of minutes) during foraging.

They are "earless/true seals" (Family Phocidae): no external ear flaps and hind flippers that can't rotate forward for walking like sea lions do.

Two main breeding concentrations are recognized: a Northwest Atlantic stock (e.g., off Labrador/Newfoundland and Gulf of St. Lawrence region) and a Northeast Atlantic stock (Greenland Sea/Jan Mayen area), both tied to drifting pack ice.

Unique Adaptations

  • Inflatable nasal hood (males): a specialized nasal structure used as a visual and acoustic display amplifier during mating competition.
  • Eversible red nasal "balloon" (males): an additional membrane that can be protruded from one nostril in high-intensity threat displays-highly distinctive among mammals.
  • Deep-diving physiology: high blood volume, oxygen storage (hemoglobin/myoglobin), and dive bradycardia support repeated cold-water dives to great depths.
  • Thick blubber layer: insulation and energy storage crucial for life in near-freezing waters and for supporting fasting periods around breeding/molting.
  • Streamlined true-seal body plan: powerful rear flippers optimized for efficient underwater propulsion (with limited on-land mobility as a tradeoff).
  • Ice-associated life history: timing of birth, nursing, and early pup development is synchronized to ephemeral pack-ice conditions.

Interesting Behaviors

  • Pack-ice breeding and pupping: females give birth on drifting sea ice, typically to a single pup, timing reproduction to seasonal ice formation.
  • Explosive male displays: males posture, vocalize, and inflate the hood; escalated contests may include lunging and biting on the ice to secure mating opportunities.
  • Extremely rapid weaning: mothers nurse intensively for ~4 days, then depart; pups undergo a short fasting period as they transition to independent foraging.
  • Cold-water pursuit foraging: diet includes fish (e.g., capelin, herring, cod) and squid; individuals often alternate bouts of deep diving with surface recovery.
  • True-seal locomotion: on ice they move by undulating/"humping" and using foreflippers, rather than walking on all fours (a key contrast with eared seals).
  • Seasonal movements: after the ice-breeding season they disperse widely through the North Atlantic/Arctic margin to feed, often tracking productive frontal zones and ice edges.

Cultural Significance

Hooded seal (Cystophora cristata) has long been part of North Atlantic and Arctic coastal life, especially in Greenland and Atlantic Canada, giving meat, oil, and skins. Males' hood and sea-ice breeding ties make them a symbol of ice-dependent wildlife.

Myths & Legends

In Inuit and Greenlandic coastal stories, the Hooded Seal (Cystophora cristata) and other seals are linked to the Sea Woman (Sedna/Nerrivik). People honor her and hunt with respect to keep sea mammals available.

North Atlantic selkie tales say seals shed skins to become human, marry, then reclaim skins to return to sea. Tales aren’t species specific but often link to seal‑rich coasts where Hooded Seal (Cystophora cristata) appears.

Early sailors and hunters called the Hooded Seal (Cystophora cristata) the "bladder-nose seal" for its inflatable hood. The species name cristata ("crested") also points to this male feature praised in old Arctic accounts.

Conservation Status

VU Vulnerable (IUCN Red List, IUCN 3.1; species account: Cystophora cristata). Key life-history/biology used in conservation assessments: extreme sexual dimorphism (adult males ~2.5-2.6 m, commonly ~300-410 kg; adult females ~2.0-2.2 m, commonly ~145-300 kg); pups ~24 kg at birth and are weaned after ~4 days of lactation (one of the shortest lactation periods among mammals; reported in the scientific literature, e.g., Bowen et al.). Ice-associated breeder in the North Atlantic/Arctic; males use an inflatable nasal hood for display and competition. HUBS (Phocidae / North Atlantic ice-breeding seals): conservation statuses span from Least Concern (e.g., some widespread seals) through Near Threatened to Vulnerable/Endangered for several ice-dependent or regionally depleted taxa; common pressures include loss of sea ice from climate warming, incidental capture/entanglement, prey shifts from fisheries, and contaminant exposure, with some Arctic-associated populations most at risk under accelerating sea-ice decline.

Facing a high risk of extinction in the wild.

Population Decreasing

Protected Under

  • United States: Marine Mammal Protection Act (MMPA, 1972) - prohibits 'take' and regulates import/export of marine mammals and products.
  • Canada: Fisheries Act - Marine Mammal Regulations (seal hunting controlled by licensing/quotas and seasons).
  • Greenland: regulated subsistence harvest under Greenlandic management frameworks for marine mammals (rules vary by area/season).
  • Norway: national regulations governing sealing activities and marine mammal management in relevant waters.
  • European Union: restrictions on commercial trade in seal products (EU Seal Regime), reducing market-driven hunting pressure in many contexts.

Life Cycle

Birth 1 pup
Lifespan 30 years

Lifespan

In the Wild
25–35 years
In Captivity
20–30 years

Reproduction

Mating System Polygyny
Social Structure Aggregation Group
Breeding Pattern Seasonal
Fertilization Internal Fertilization
Birth Type Internal_fertilization

Hooded seal (Cystophora cristata) is strongly polygynous: large males fight on seasonal pack ice and show an inflatable nasal hood. Females are spread out, not in harems; bonds are brief. Females have one pup, nurse ~3–5 days; the mother alone cares, then leaves. Delayed implantation occurs.

Behavior & Ecology

Social Colony Group: 1
Activity Cathemeral
Diet Piscivore Greenland halibut (commonly reported as a major prey in many North Atlantic/Arctic foraging areas)
Seasonal Migratory 1,553 mi

Temperament

Generally asocial/avoidant; low social tolerance outside breeding and molt aggregations
Strong seasonal aggression in adult males during breeding: territorial/competitive behavior, threat displays, chasing and biting reported on pack ice (polygynous mating system)
Female hooded seals show strong mother focus during a very short nursing time of about four days, with lots of nursing and close mother and pup contact well documented.
High wariness to disturbance on ice; individuals typically retreat to water when approached (field observations summarized in species accounts, e.g., Burns; Kovacs & Lavigne)

Communication

Airborne calls on ice during breeding: male roars/growls and aggressive vocalizations associated with threat and contests; female-pup contact calls during the brief nursing period Summarized in phocid/hooded seal species accounts such as Burns, *Encyclopedia of Marine Mammals*, 2nd ed.
Underwater vocalizations during the reproductive season used in spacing/advertisement Reported in multiple phocid acoustic studies; species accounts summarize these as low-frequency calls used during breeding
Visual display Key species-typical signal): adult males inflate the nasal 'hood' and evert the red nasal septum ('balloon') during display and competition; used as an amplified visual threat/advertisement signal on pack ice (classic, repeatedly documented hallmark behavior; summarized in Burns, *Encyclopedia of Marine Mammals*, 2nd ed.
Postural/behavioral threat signals: open-mouth displays, head thrusts, lunges, and body elevation; escalates to fighting/biting among males during breeding
Tactile communication: mother-pup contact (nuzzling, close physical positioning) during the short nursing interval; limited affiliative contact outside maternal care
Acoustic-visual coupling: hood inflation commonly coincides with vocal/aggressive sequences, functioning as a multimodal display during male contests Summarized in species accounts

Habitat

Open Ocean Coastal Beach Rocky Shore Deep Sea Seabed/Benthic
Terrain:
Coastal Island Rocky

Ecological Role

Upper-level marine predator (mesopredator to apex predator depending on local community) linking deepwater/pelagic fish and squid production to higher trophic levels in North Atlantic-Arctic ecosystems.

Regulation of fish and squid populations (top-down control) Energy transfer from deep/pelagic foraging zones to surface/ice habitats via movement and excretion Nutrient recycling (release of nitrogen/phosphorus through waste) supporting local productivity Provision of prey/biomass to apex predators and scavengers (e.g., polar bears, killer whales, sharks) through predation events and carcasses

Diet Details

Main Prey:
Greenland halibut Atlantic herring Capelin Polar cod Redfish Sand eel Squid +1

Human Interaction

Domestication Status

Wild

Hooded seals (Cystophora cristata) are not domesticated and were never bred by people. Humans mainly hunt them or study them (tagging, monitoring). Males are much larger than females (males ~2.5–2.6 m, 300–410 kg; females ~2.0–2.2 m, 145–300 kg). Pups nurse only 3–5 days. They breed on Arctic/North Atlantic pack ice and can live about 35 years.

Danger Level

Moderate
  • Bites and crushing injuries: large body size plus defensive behavior can cause severe lacerations or fractures, especially during handling (entanglement response, rehabilitation, or if approached on ice/shore). Adult males can be notably aggressive during breeding displays and competition (inflatable nasal hood/"red balloon" display accompanies threat behavior).
  • Zoonotic infection risk from bites/handling: 'seal finger' (classically associated with handling pinnipeds; bacterial infections including Mycoplasma spp. have been implicated), plus general marine-mammal zoonoses (e.g., Brucella spp. exposure risk in some pinniped contexts).
  • Operational hazards for humans in shared habitats: interactions occur in remote, icy environments (pack ice, cold-water operations), where the primary risk to humans is often environmental/working-condition related rather than direct attack.

As a Pet

Not Suitable as Pet

Legality: Hooded seal (Cystophora cristata) are generally illegal to keep as pets. In the U.S. the MMPA bans having them without federal permits; Canada, Greenland, and Europe have similar rules. Only accredited facilities (rehab, research, public display) may hold them.

Care Level: Expert Only

Purchase Cost:
Lifetime Cost: $1,000,000 - $5,000,000

Economic Value

Uses:
Subsistence harvest (Inuit/Indigenous communities, where legal) Commercial sealing (historical and limited modern; tightly regulated) Wildlife management and conservation monitoring Scientific research (physiology, diving behavior, climate/ice ecology) Bycatch-related economic impacts (damage/loss in fisheries; mitigation costs)
Products:
  • Pelts/skins (historically used for leather/fur; trade now heavily restricted in many markets)
  • Blubber oil (historically significant)
  • Meat (primarily subsistence/local use where permitted)
  • Scientific data products (telemetry datasets, population assessments informing policy/quotas)
  • Ecosystem services value (indicator species for sea-ice change; non-consumptive value)

Relationships

Related Species 8

Harp Seal
Harp Seal Pagophilus groenlandicus Shared Family
Gray Seal
Gray Seal Halichoerus grypus Shared Family
Harbor seal
Harbor seal Phoca vitulina Shared Family
Bearded Seal Erignathus barbatus Shared Family
Ringed Seal Pusa hispida Shared Family
Northern Elephant Seal Mirounga angustirostris Shared Family
Southern Elephant Seal Mirounga leonina Shared Family
Ribbon Seal Histriophoca fasciata Shared Family

Ecological Equivalents 5

Animals that fill a similar ecological role in their ecosystem

Harp Seal
Harp Seal Pagophilus groenlandicus North Atlantic, ice-breeding, pelagic-feeding phocid seal that overlaps hooded seals on pack ice and in offshore foraging areas. Both species are seasonal migrants tied to ice edges and productive frontal zones.
Ringed Seal Pusa hispida Arctic, ice-associated seal that uses sea ice for resting and breeding; overlaps with hooded seals in Arctic and subarctic waters and shares reliance on ice habitat, although ringed seals more often use landfast ice and snow lairs rather than open pack ice.
Bearded Seal Erignathus barbatus Large Arctic phocid that uses sea ice for haul-out. Shares a cold-water distribution with hooded seals but occupies a more benthic-feeding niche, making it a useful ecological comparator for ice-associated pinnipeds.
Walrus
Walrus Odobenus rosmarus Large, ice-associated pinniped in Arctic seas. Shares dependence on sea ice as a platform for resting and breeding and is exposed to similar climate/ice-loss pressures, despite a different diet (benthic mollusks vs. fish and squid).
Northern Elephant Seal Mirounga angustirostris Deep-diving phocid ecological analog: both are extreme divers among pinnipeds. Hooded seals have been recorded performing deep, long-duration dives (reported >1,000 m and >50 min), comparable to northern elephant seals in foraging strategy (targeting mesopelagic and bathypelagic prey).

“The seal with the inflatable red nose.”

A casual look at a male hooded seal reveals a typical large true seal. This means he has a blubbery, cylindrical body, no ear flaps, small flippers, and a tail that makes him an excellent swimmer but clumsy on the ice floes where he usually lives. But then, if the hooded seal is about to go for a dive or wants to impress a rival or a female, the skin on top of his head can balloon to the size of two footballs. Not only this, but he can shut off one of his nostrils and fill the other with so much air that another balloon, this one bright red, pops out of his nose. Both the balloon on the head and the one that comes out of the animal’s nose can produce sounds that warn rivals and would-be predators and attract females.

5 Incredible Hooded Seal Facts!

Here are some facts about this unusual pinniped:

  • The babies are born precocial, which means they can take care of themselves shortly after birth. They only nurse from four days to two weeks, then they’re completely on their own. No other mammal has such a short lactation period, but the high-fat content in the seal’s milk goes a long way.
  • They can dive to depths of over 3000 feet and can stay underwater for 50 minutes.
  • Males develop their famous hood when they’re about four years old.
  • They have the largest nostrils of any seal.
  • The hooded seal cow has very rich milk. It’s about 60 to 70 percent fat.

Hooded Seal Scientific Name

This species’ scientific name is Cystophora cristata. Cystophora is Greek for “bladder-bearer,” and describes the bladder-like structure found on the male hooded seal’s head. Cristata is Latin for “crested.” There are only one species of hooded seals, though biologists separate them into two populations. There’s the population in the northeast Atlantic and a population in the northwest Atlantic.

Hooded Seal Appearance

The hooded seal is a large seal with silver-gray fur with black spots. They have black faces and small limbs. Though their limbs are small, these seals are expert swimmers and divers. Males are a little longer than females but weigh much more. They can weigh 661 pounds on average to a female’s 353 pounds, and of course, they can inflate their nasal passages.

Hooded seals also differ from other seals in the adaptations nature made to their teeth. Unlike other seals, they have two incisors in their upper jaw and one incisor in their lower jaw.

A male hooded seal can weigh, on average, 200 pounds more than a female.

The Red Nose of a Male Hooded Seal

The male hooded seal’s “hood” and red nose have long been objects of fascination for biologists. They are the result of a cavity or bladder in the seal’s nose that can stretch. When it’s not inflated, the bladder hangs down over the seal’s mouth. When he inflates it, it makes his head look almost twice as big as it is, which intimidates opponents and is supposed to impress females. When the hood is partially inflated, the seal also blows up the stretchy septum in their left nasal cavity till it resembles a red balloon. When the seal shakes these balloons, they can make whooshing and pinging noises that are audible over land and in the water.

Hooded Seal Behavior

Hooded seals are largely solitary until the breeding season, which is unusual. They don’t establish social hierarchies or fight over territories, though male seals will compete for an area around a female. Even after they give birth, hooded seal cows and their pups don’t stay together long.

Seals mostly eat during the fall and winter and stop eating during the spring and summer when they breed and shed their old fur. This means that the mother doesn’t eat while they’re nursing their pups even as the pups gain 15 pounds every day on their very fatty milk until they’re weaned. She loses 15 to 22 pounds every day in the meantime. After the spring breeding season, the seals enter the water again to find food, then haul out in the summer to molt.

A hooded seal pup can gain 15 pounds a day until it’s weaned from its mother.

Habitat

Hooded seals spend most of their time swimming and diving in the cold waters of the North Atlantic Ocean and the Arctic Ocean. They haul out on ice floes or on land that is covered with ice and are careful to migrate to areas where ice floes are plentiful.

Diet

The seal’s diet is mainly crustaceans and fish. They are partial to the capelin, which is a type of smelt found in cold northern waters. This small fish gives the seal the fat it stores in its blubber and utilizes when it doesn’t eat. Other foods are squid and octopus, cod, redfish, herring, and halibut.

Hooded Seal Predators and Threats

Humans have been the main predators of hooded seals. The animals have been hunted since at least the 18th century and were harvested so indiscriminately that it was difficult for their populations to recover. They were first killed for oil and to make leather out of their hides. Then, even baby seals were killed for their beautiful fur, and their mothers were often killed as they tried to protect them. Some people are subsistence hunters of hooded seals, but the seal has been so depleted by commercial hunting that even subsistence hunting is problematic. Seals are also found stranded on beaches and get entangled in nets meant for other marine animals.

Less rapacious predators of the animal are killer whales, sharks, including the Greenland shark, and polar bears. Seals, which don’t move well out of the water, are especially vulnerable when they are breeding or molting on pack ice. Smaller predators include heartworms, which infest the animal’s heart and lung arteries and can shorten its life. These animals that are held in captivity also die from tuberculosis and infection.

What eats the Hooded Seal?

Hooded seals are eaten by killer whales, sharks, and polar bears.

What does it eat?

The hooded seal eats fish, marine mollusks, and marine crustaceans. Though the physical adaptations of the adults allow them to dive deeply to find this food, newly weaned pups have to catch their prey close to the shore.

Hooded Seal Reproduction and Life Cycle

The breeding season for the hooded seal is in spring. Since she nurses her pup for such a short time, a hooded seal cow attracts the attention of males shortly after she gives birth. The males inflate and sound their balloons both to impress her and to threaten each other. Sometimes they will simply shove each other off the pack ice. The bull and cow mate in the water, then he’ll go off and find another cow. In the meantime, the first cow is pregnant for about eight months. The mother is fiercely protective of the baby for as long as it’s nursing.

Hooded seal - mother and pup

Mother seals are very protective of their pup while it’s still nursing.

Hooded Seal Population

The hooded seal population is believed to be 650,000 animals according to the MarineBio Conservation Society. Still, the animal is listed as vulnerable. The northwest Atlantic population is either stable or increasing, but the northeast Atlantic population is still in decline.

Conservation Efforts

Though the hooded seal is still hunted in areas, it is protected by the Marine Mammal Protection Act of 1972 and is subject to a strict quota. No more than 10,000 hooded seals can be caught in any given year around the world.

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Sources

  1. NOAA Fisheries / Accessed August 23, 2021
  2. ScienceDirect / Accessed August 23, 2021
  3. MailOnline / Accessed August 23, 2021
  4. Wikipedia / Accessed August 23, 2021
  5. marinebio / Accessed August 23, 2021
  6. Animal Diversity Web / Accessed August 23, 2021
A-Z Animals Staff

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Hooded Seal FAQs (Frequently Asked Questions)

Hooded seals are carnivores. They eat fish and other marine life.