How to Tell the Difference Between Seals and Sea Lions

The Distinct Physical Differences Between Seals and Sea Lions:

Seals and sea lions, collectively known as pinnipeds, share similarities in their semi-aquatic lifestyles but exhibit several distinct physical differences. Understanding these variations can aid in the identification of these fascinating marine mammals:

Body Shape:

• Seals typically have a more streamlined, torpedo-shaped body, which is well-suited for efficient swimming and diving. Their bodies are elongated, with relatively short, stubby flippers that they use for propulsion underwater.
• Sea lions, on the other hand, have a more robust and muscular build, with longer, more defined foreflippers. Their bodies are more elongated and cylindrical compared to seals, giving them a more agile appearance both in water and on land.

Calif Sea Lions hauled out the rocks

A family of Harbor Seals

Limb Structure:

• Seals have short, flipper-like limbs that are not well adapted for weight-bearing or walking on land. Their hind flippers are fused together and cannot rotate forward, so they move on land by wriggling or undulating their bodies.
• Sea lions have longer, more flexible foreflippers that they use to propel themselves through the water with speed and agility. Their hind flippers are capable of rotating forward, allowing them to walk on all fours and even stand upright on land.

an adult Male Sea Lion

Harbor seal on the beach

Ear Structure:

• Seals lack visible external ear flaps, with only small openings for hearing. Their ears are more recessed and covered by fur, which helps streamline their bodies for efficient swimming.
• Sea lions have prominent external ear flaps that are easily visible, giving them a more distinct appearance. These external ears can be rotated to detect sounds both in water and on land, enhancing their auditory capabilities.

Sea Lion

a young Elephant Seal

Facial Features:

• Seals typically have a short, blunt snout with large, soulful eyes. Their nostrils are relatively small and lack mobility, remaining closed underwater to prevent water from entering.
• Sea lions have a more pronounced, elongated snout with a larger mouth opening. Their nostrils can close tightly when submerged, but they can also flare open to facilitate breathing while swimming at the surface.

Behavioral Differences:

• Seals are generally more solitary and elusive, often spending long periods at sea foraging for food. They tend to haul out onto land primarily for breeding, molting, and resting.
• Sea lions are more social and gregarious, often forming large colonies on beaches and rocky shorelines. They are known for their vocalizations, agility, and playful behavior both in water and on land.

By recognizing these physical and behavioral distinctions, observers can more accurately identify whether they are observing a seal or a sea lion in their natural habitat.