Earless seal, also known as true or crawling seal, is a commonly used name to refer to several species of seals in the family Phocidae, including the harbor seal, grey seal, and ringed seal. Unlike eared seals, they lack external ears. Instead, they have small openings on the sides of their heads.
Their powerful rear flippers propel them through the water, and they can hold their breath for a long period of time. These streamlined creatures have adaptations that allow them to thrive in harsh environments of the world’s oceans, from the icy waters of the Arctic to the Pacific and Atlantic temperate seas.
Continue reading to understand more about the complex behaviors and characteristics that make the earless seals worth the attention.
Appearance
Earless seals are generally large and bulky, with streamlined bodies perfectly adapted for life in the water. Males are typically larger than females. They range in size from 1.2 m and 45 kg (like the Baikal seal) to 5 meters and 3,200 kg (like the northern elephant seal, which is the largest member of the order Carnivora).
Some are dark gray or black, while others can be brown, tan, or even silvery-white. Many also have unique patterns or spots.
Their limbs have evolved into flippers. The front flippers are short and have claws, while the hind flippers are longer and more paddle-like. They cannot rotate their hind flippers underneath their bodies, so they move on land by wriggling their bodies in a caterpillar-like motion.
From their powerful jaws and sharp teeth to their ability to hold their breath for extended periods, these mammals have evolved various adaptations that allow them to hunt, navigate, and communicate underwater.
They have large, round heads with big, forward-facing eyes that give them excellent underwater vision. Their noses are small and they have whiskers which help them detect prey.
Most species have a layer of fat beneath their skin that helps them stay warm in cold water.
Habitat
Earless seals are found in various habitats throughout our oceans, from the icy Arctic and Antarctic waters to the Pacific and Atlantic temperate seas. They can be found in various environments, including Open Oceans, coastal waters, and estuaries.
They haul themselves out of the water onto land or ice floes, where they rest, mate, and give birth.
However, as we’ve seen, they are well-suited to life in the water and spend much of their time swimming and diving in search of food.
Diet
These seals can dive to great depths in search of food, with some species able to stay underwater for several hours.
Earless seals are carnivorous and feed primarily on fish, squid, and crustaceans, although the specific types of prey vary by species and geographic region.
Some species, such as the harbor seal, feed primarily on small fish. However, others, such as the leopard seal, are apex predators capable of hunting larger prey, including penguins and other seals.
Reproduction
Earless seals mate in the water, and females give birth to a single pup on land or ice floes. The gestation period varies between species but generally lasts six to eleven months.
After birth, the mother nurses her pup for several weeks, providing it with fatty milk that helps it grow and stay warm. Once the pup is weaned, the mother will leave it to fend for itself. The young must learn how to swim, dive, and find food to survive at this time.
Threats
Earless seals face various threats in their natural environment, including climate change, pollution, hunting, and fishing.
As the climate changes, sea ice is melting at an alarming rate, affecting the seals’ habitat and food sources. Pollution from oil spills and plastic waste also poses a significant threat to earless seals, as it can contaminate their food and harm their health.
Hunting is another major threat to earless seals, as they have been hunted for their meat, oil, and fur for centuries. While hunting is now illegal in many parts of the world, it still occurs in some regions, particularly in Alaska and Canada. Indigenous communities rely on seals for food and clothing in these places.
At the same time, some anglers frequently kill earless seals to protect their catch.
5 More Facts About Earless Seals
- Earless seals are called “true seals” because they belong to the family Phocidae, while their cousins, like the sea lions and fur seals, belong to the family Otariidae.
- There are 18 species of earless seals, including the harbor, leopard, and elephant seals.
- Earless seals can hold their breath for up to 90 minutes, allowing them to dive to great depths in search of food.
- Some earless seals can stay underwater for several hours at a time, using their slow metabolism and ability to conserve oxygen to survive.
- Earless seals have been known to travel long distances for food, with some species swimming more than 10,000 miles in a year.
FAQs
How do earless seals find food in dark or murky waters?
Earless seals rely heavily on their incredibly sensitive whiskers (vibrissae). These whiskers act as underwater antennae, detecting vibrations and subtle water movements caused by prey. This adaptation allows them to hunt effectively even in low-visibility conditions.
How do earless seals stay warm in cold ocean waters?
Earless seals combat cold ocean temperatures through a combination of physiological and behavioral adaptations. A thick layer of blubber beneath their skin provides excellent insulation, preventing excessive heat loss. They also regulate blood flow, reducing heat loss from extremities and redirecting warmth to vital organs.
What makes earless seals unique in their hunting and diving abilities?
Earless seals, or true seals, are remarkable divers and hunters. They can dive to great depths (over 5000 feet for some species) and stay underwater for up to two hours, thanks to their ability to slow their heart rate and store large amounts of oxygen in their muscles. This allows them to hunt effectively in deep waters, catching prey such as fish and squid.
Are earless seals extinct?
No, they are not extinct. Several species of earless seals are currently found throughout the world’s oceans. However, some species have experienced significant population declines in recent years, particularly in the Arctic and Antarctic regions. For example, the population of the ribbon seal, which is found primarily in the Bering Sea, has decreased by over 60% in the last three decades.
Are earless seals friendly to humans?
They are typically not aggressive toward humans. However, they may become defensive if they feel threatened or cornered. So, people should maintain a safe distance from earless seals and avoid disturbing them in their natural habitat.
It is illegal to approach or harass earless seals in some regions, such as Alaska. In other words, there are penalties for violating these regulations in these places.
