Hooded Seal

Quick Take

• This seal can pull a bright red balloon out of its nose. Find out why it does it.
• One mammal nurses its young for a shorter time than any other. How does the baby survive on its own?
• A mother loses weight fast while her pup balloons. What is going on behind that lopsided trade?
• Hunters nearly wiped out these seals, and one rule now limits the yearly catch. Is it enough?

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

• The babies are born precocial, which means they can take care of themselves shortly after birth. They only nurse for about four days, 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 3,000 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.

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 is only one species of hooded seal, though biologists separate them into two populations. There’s the population in the northeast Atlantic and a population in the northwest Atlantic.

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. Males can weigh about 423 to 776 pounds while females weigh 320 to 660 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.

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.

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 she’s nursing her pup, even as the pup gains 15 pounds every day on her very fatty milk until it’s 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.

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.

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 the Hooded Seal 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.

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.

Population

The hooded seal population is believed to be 650,000 animals according to the MarineBio Conservation Society. Still, the animal is listed as Endangered by the IUCN. 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 some areas, it is protected in U.S. waters by the Marine Mammal Protection Act of 1972, and hunts elsewhere are regulated. Canada has set a total allowable catch of 8,200 hooded seals per year, Norway has banned commercial hunting since 2007, and Greenland controls its hunt through permits and catch reporting.