What’s The Difference Between a Seal and a Sea Lion?

Pinnipeds are fascinating marine mammals that have captivated the curiosity of many. Among this diverse group are seals and sea lions, two species often mistaken for one another.

While they share common aquatic habitats and some aspects of their lifestyles, they exhibit a myriad of differences that set them apart. This article aims to delve into these distinctions, providing clarity and understanding about these remarkable creatures of the sea.

Seal vs. Sea Lion: Physical Differences

Body Shape

Seals and sea lions exhibit noticeable differences in their body shapes. Seals have a more streamlined, torpedo-like shape which aids in efficient swimming.

Their bodies are well-adapted to a life spent predominantly in the water. Sea lions, on the other hand, have a bulkier build, with a larger torso and a more pronounced neck.

Fur and Skin

When it comes to their covering, seals have a layer of blubber under their skin which helps in insulation, making them well-suited to colder waters. They possess a short, dense fur coat.

Sea lions have a thinner layer of blubber, and their fur is also shorter but less dense compared to seals.

Ears

One of the most distinct differences between seals and sea lions is their ears. Seals have internal ear holes with no external ear flaps, giving their heads a smoother, more streamlined appearance.

Sea lions, conversely, have visible external ear flaps, which are easily noticeable and contribute to their overall different head shape.

Flippers

Seals and sea lions use their flippers differently, especially on land. Seals have smaller front flippers and navigate on land by wriggling their bodies in a caterpillar-like motion. Their rear flippers do not rotate, making them less agile on land.

Sea lions have larger, more muscular front flippers which they use to propel themselves in water and ‘walk’ on land, as their rear flippers can rotate forward, providing them with better mobility out of the water.

Seal vs. Sea Lion: Behavior and Lifestyle

Social Behavior

Seals and sea lions exhibit marked differences in their social structures and behaviors. Seals tend to be more solitary and are often found alone or in small groups. They have specific territories and are less social than sea lions.

On the flip side, sea lions are highly social animals. They gather in large colonies on shorelines and are known for their playful and noisy interactions. The lively dynamics within a sea lion colony are a stark contrast to the more subdued nature of seals.

Vocalizations

Both species are vocal, but the sounds they make and the frequency of their vocalizations differ. Seals generally make softer, lower-pitched sounds such as grunts and growls. Their vocalizations are less frequent and are often made underwater.

Sea lions are quite the opposite; they are known for their loud barks and constant vocalizations, especially within a colony. The barking of a sea lion is one of their most recognizable and distinctive features.

Movement on Land

When it comes to moving on land, seals and sea lions again show distinct differences. Seals have an awkward, inching movement, pulling themselves along with their front flippers and undulating their bodies. Their hind flippers trail behind, providing little assistance.

Sea lions, with their larger front flippers and rotatable hind flippers, are able to ‘walk’ on all fours, displaying greater agility and speed on land compared to their seal counterparts.

Seal vs. Sea Lion: Habitat and Range

Geographical Distribution

Seals and sea lions are found in oceans all over the world, but they prefer different types of environments. Seals are generally found in colder waters and are well-adapted to life in Arctic and Antarctic regions. They have a widespread distribution, with species inhabiting both the northern and southern hemispheres.

Sea lions, in contrast, are typically found in warmer waters along coastlines and islands. They are more commonly associated with the Pacific Ocean, though they are also found in other parts of the world.

Preferred Habitats

Seals are known to inhabit a variety of marine environments, from the icy waters of the polar regions to temperate seas. They are well-suited to life in the water and can often be found far from shore.

Sea lions, on the other hand, prefer coastal habitats. They are often found on rocky shores, sandy beaches, and nearshore islands. Their colonies are typically located in areas that provide easy access to both land and water, reflecting their adaptable nature and ability to thrive in different environments.

Seal vs. Sea Lion: Diet and Hunting

Prey

Seals and sea lions have diverse diets, but there are some general trends in what they prefer to eat. Seals typically feed on fish, squid, and crustaceans. Some larger seal species, like the leopard seal, also feed on other seals or penguins.

Sea lions, on the other hand, primarily eat fish and squid. They have been known to consume a wider variety of fish species compared to seals.

Hunting Techniques

Seals are generally solitary hunters, relying on stealth and agility to catch their prey. They use their whiskers to detect the vibrations of their prey in the water, and they can dive deep and swim quickly to pursue their food.

Sea lions also hunt alone, but they are known to work together to herd fish into shallow areas where they are easier to catch. They are strong and fast swimmers, using their powerful front flippers to propel themselves through the water.

Seal vs. Sea Lion: Reproduction and Lifespan

Mating Habits

Seals and sea lions have different mating systems. Many seal species have a polygynous mating system, where a single male mates with multiple females. The males establish territories and fight to maintain access to a group of females.

Sea lions also have a polygynous mating system, but they form breeding colonies where several males establish territories and compete for access to females.

Offspring

Both seals and sea lions give birth to live young and care for them until they are old enough to fend for themselves. Seal pups are usually more precocial, meaning they are born in a more developed state and are able to swim and fend for themselves at an earlier age.

Sea lion pups are more altricial, requiring more extended care from their mothers. However, sea lion pups are known to be more playful and social, often seen interacting with other pups in the colony.

Lifespan

The lifespan of seals and sea lions varies depending on the species, but in general, seals tend to live longer than sea lions. Some seal species can live up to 30 years or more in the wild, while sea lions typically live between 20-30 years.

However, these lifespans can be significantly shorter in the wild due to predation, human activities, and other factors.

Seal vs. Sea Lion: Conservation Status

IUCN Red List Status

Seals: The IUCN Red List status of seals varies widely among different species. For example, the Mediterranean monk seal (Monachus monachus) is classified as “Endangered,” while the harbor seal (Phoca vitulina) is listed as “Least Concern.”

Sea Lions: Similar to seals, sea lion species have varying conservation statuses. The Steller sea lion (Eumetopias jubatus) is categorized as “Near Threatened,” while the California sea lion (Zalophus californianus) is listed as “Least Concern.”

Threats

Both seals and sea lions face a range of threats, many of which are influenced by human activities. Overfishing can deplete their food sources, while climate change and habitat loss can disrupt their breeding and feeding grounds.

Entanglement in fishing gear and marine debris is another significant threat, along with pollution and oil spills that can contaminate their habitat and food.

Seals are also at risk from hunting in certain regions. Some species of seals are hunted for their fur, oil, and meat, which can lead to population declines if not properly managed. Sea lions face similar threats but have also been subject to culling in some areas where they are viewed as a threat to fisheries.

Conservation Efforts

Numerous conservation initiatives are in place to protect seals and sea lions. These include establishing protected areas, enforcing fishing regulations to prevent overfishing, and implementing measures to reduce bycatch. Rehabilitation programs also exist to care for injured or stranded individuals, with the aim of releasing them back into the wild.

Education and awareness-raising are crucial components of conservation efforts, helping to reduce human-wildlife conflict and promote coexistence. Research and monitoring are ongoing to better understand the needs of these species and inform conservation strategies.

How to Identify Seals and Sea Lions in the Wild

When observing these animals in their natural habitats, pay attention to their physical characteristics and behaviors. Seals typically have a more streamlined body and lack visible ear flaps, while sea lions have a robust body and visible external ear flaps. Sea lions are also more vocal and social, often seen barking loudly and congregating in large groups.

Watch their movement on land; seals move in a caterpillar-like fashion, while sea lions can “walk” on their flippers. In water, seals are more agile and graceful swimmers, using their back flippers to propel themselves, whereas sea lions use their powerful front flippers for swimming.

Frequently Asked Questions