Sea lions and seals are marine mammals, both belonging to the group known as pinnipeds. Despite their similar appearances and shared aquatic environments, they exhibit distinct characteristics. This article clarifies the unique features that differentiate sea lions from seals.
Physical Characteristics
One noticeable distinction between sea lions and seals lies in their ears. Sea lions possess small, external ear flaps, known as pinnae, visible on the sides of their heads. In contrast, true seals lack these external ear flaps, having only small ear holes that are less apparent.
Their flippers also present clear variations. Sea lions feature large, paddle-like front flippers covered mostly in skin, which they use for propulsion through water and for supporting their weight on land. True seals, on the other hand, have shorter, fur-covered front flippers with claws, which are primarily used for steering in the water. The structure of their hind limbs further differentiates them. Sea lions can rotate their hind flippers forward and underneath their bodies, enabling them to “walk” on all fours on land. Seals cannot rotate their hind flippers in this manner; their hind flippers extend backward, making terrestrial movement more challenging.
Regarding body shape and fur, seals have a more streamlined, torpedo-shaped body that appears rounder, contributing to their agility in water. Their fur is often shorter and denser, sometimes appearing spotted. Sea lions tend to have a more robust and muscular build with a coarser, shorter coat that usually appears brown.
Behavior and Habitat
The anatomical differences between sea lions and seals directly influence their movement on land. Sea lions can lift their bodies off the ground and walk, or even gallop, across terrestrial surfaces with surprising agility. This mobility allows them to navigate rocky coastlines and beaches with ease. Seals are less mobile on land; they move by “galumphing” or wriggling their bodies in a caterpillar-like motion. This makes their terrestrial movement appear more cumbersome.
Vocalizations also set these marine mammals apart. Sea lions are known for their loud, boisterous barks and roars, used extensively for communication within their social groups. Seals are much quieter, communicating through softer grunts, hisses, or growls. Their overall vocal repertoire is less varied and less frequent than that of sea lions.
Social structures differ significantly. Sea lions are highly social animals, often congregating in large groups called colonies or herds that can number in the thousands on land. They frequently haul out together on beaches and rocks. Seals, conversely, are often more solitary, especially when in the water. While they may gather in smaller groups, particularly during breeding seasons, their social interactions are less extensive than those observed in sea lion colonies.
Habitat preferences show variations. Sea lions are commonly found in temperate to subarctic waters, often inhabiting rocky coasts and islands, and can be seen on human-made structures like docks. They spend considerable time ashore.
Seals are more widespread, found in various cold and temperate waters, from the Arctic to tropical regions, with some species preferring icy environments or secluded beaches. Seals are more adapted to aquatic life.
Easy Identification Tips
Observing a few key features can help distinguish between a sea lion and a seal. First, check for visible ears. If the animal has small, external ear flaps, it is a sea lion. If you only see a small ear hole and no external flap, it is a seal. This is often the quickest and most reliable visual cue.
Next, pay attention to how the animal moves on land. If it can rotate its hind flippers forward and use all four limbs to walk or gallop, it is a sea lion. If it moves by wriggling its body in a caterpillar-like motion, unable to bring its hind flippers under its body, then it is a seal.
Finally, listen to their vocalizations. Sea lions are known for their loud, continuous barking and roaring. If the animal is making loud, boisterous sounds, it is likely a sea lion. Seals, in contrast, are much quieter, communicating with softer grunts, hisses, or growls. These auditory cues, combined with visual observations of ears and movement, provide effective methods for identification.