What Are the Differences between Seals and Sea Lions?

At first glance, especially to the untrained eye, it is hard to see any difference between seals and sea lions. Although these two animals look similar, however, there are big differences in their physical composition, social organization and even in their familial classification.

Despite their appearance, the two animals are not very closely related to one another. Seals are from the family Phocidae, while sea lions are from the family Otariidae. Sea lions are more closely related to walruses, even though it is far easier to differentiate the two by simply looking at them.

One of the biggest physical differences between sea lions and seals are their ears. In fact, as members of the order Pinniped, to which they both belong, they are termed either true seals or eared seals. Sea lions, the eared seals, have external ear flaps located on either side of their head covering the actual opening of the ear. Seals, on the other hand, do not have ear flaps. They have tiny holes on either side of their head through which they hear, but that are barely visible without close inspection.

Another major difference is in their flippers. Sea lions have large front flippers that help balance their heavy bodies. They also have back flippers that they can easily rotate when they are on land. These enable them to walk somewhat gracefully. Seals have far smaller front flippers that do not offer leverage or balance. Their rear flippers do not rotate, rendering them unable to walk gracefully on land at all. Rather, when they are out of the water, seals have to slither along in an extremely awkward manner.

The last and most significant difference between these animals is their social organization. Sea lions are gregarious and prefer to live in large groups usually of the same sex. Males and females tend to enjoy each other’s company most during mating season, beginning in early June. Seals are not as social, although females tend to gather in groups during mating season to protect themselves from competitive males looking to mate.

Seals and sea lions are distinguished by their flippers and ears. Seals have small flippers and lack external ear flaps, moving on land by wriggling on their bellies. Sea lions, on the other hand, have larger, stronger flippers and visible external ear flaps, allowing them to 'walk' on land using their flippers.

Both seals and sea lions are vocal, but sea lions are notably more vocal on land, often heard barking loudly in colonies. Seals tend to be quieter on land but can produce soft grunts and whistles. Their vocalizations are an essential part of their social interactions within their respective groups.

Seals and sea lions have different swimming styles due to their flipper size and flexibility. Seals use their rear flippers side-to-side like a fish's tail to propel themselves in water, while sea lions use their larger, more flexible front flippers in a rowing motion, giving them greater agility and speed.

Sea lions are known for their sociability, often seen resting in large groups on shorelines and engaging in playful interactions. Seals are more solitary, coming together mainly during breeding seasons. While both species are social to some degree, sea lions exhibit more gregarious behavior.

Both seals and sea lions are carnivorous, feeding on a variety of marine life such as fish and squid. However, their hunting methods differ slightly due to their physical capabilities. Sea lions, with their agility, may chase down prey in the water, while seals rely more on stealth and ambush techniques.

Conservation concerns for seals and sea lions vary by species and location. Climate change, habitat loss, and human activities impact them differently. For instance, according to the International Union for Conservation of Nature (IUCN), certain seal species are more threatened by diminishing ice habitats, while entanglement in fishing gear is a significant threat to some sea lion populations.