seals vs. sea lions: what’s the difference?

Seals and sea lions—they’re one and the same, right? Not quite. While both are carnivorous, semi-aquatic marine mammals belonging to the suborder Pinnipeds (Latin for “fin-footed”), they are quite different in many ways. Let’s look at some key differences between the two. 

how they look   

Seals belong to the family Phocidae, within which there are 18 living species including harbor seals, leopard seals and elephant seals. They’re also known as “true seals” or “earless seals,” even though they don’t lack ears altogether—they just have small ear holes and no external ear flaps.  

Sea lions belong to the family Otariidae, which includes six living species of sea lions and eight living species of fur seals. Also referred to as “eared seals,” sea lions do have visible external ear flaps.  

You can also note key differences between seals and sea lions by looking at their flippers. Seals have shorter front and hind fur-covered flippers with long claws. In comparison, sea lions have longer skin-covered flippers with claws on the hind flippers, which they use to scratch and groom themselves.  

how they move    

Both seals and sea lions are agile, graceful swimmers thanks to their flippers, but their movements in the water and on land are very different from one another.  

To propel themselves through water, seals use their powerful hind flippers, fanning them out and moving them in a side-to-side motion. For sea lions, it’s just the opposite—by using their large front flippers for swimming and their back flippers for steering, sea lions are among the fastest swimming pinnipeds, reaching speeds of up to 25 miles per hour. 

On land, there are also noticeable differences in movement between the two. Sea lions have much slimmer bodies and can rotate their hind flippers under their bodies to walk, or even gallop quickly on all fours. Seals are rounder in appearance and move much more awkwardly on land. They are unable to rotate or walk on their much smaller flippers; a seal’s movement on land is more caterpillar-like. They inch their bodies along in a movement known as “galumphing.”  

how they sound 

Both seals and sea lions produce vocalizations to communicate, with sea lions being the chattier of the two. A repertoire of barks, growls and groans helps sea lions recognize each other, establish and defend territories, and engage in other social interactions. Seals tend to be much quieter; they use growls and moans to communicate, but they don’t bark like sea lions.  

where they live 

Seals can be found in polar, temperate, and tropical regions—especially in the North Atlantic, the North Pacific, and the Southern Ocean. Their preferred habitat can vary greatly among species; some prefer areas with sandy beaches, others live on rocky ledges or pack ice, and certain species can be found in fresh water. 

Sea lions are found on coastlines, islands with sandy beaches, and rocky ledges from the subarctic to tropical waters in the Northern and Southern Hemispheres (with the exception of the northern Atlantic, where there are no sea lions).  

how IFAW helps seals 

IFAW was founded on the mission of ending the commercial seal hunt in Canada. We travelled to the ice to observe and document the annual slaughter, bringing international media, politicians, and veterinary experts with us to observe the cruelty first-hand. Since then, our work has helped bring about monumental changes like the 2009 EU ban on seal products. We continue to urge the Government of Canada to adopt sustainable alternatives to the commercial seal hunt—ones that can support the economy and local communities while protecting seals.  

On Cape Cod in the United States, our Marine Mammal Rescue & Research team is revolutionizing the way we rescue entangled seals. One method, developed in partnership with The Marine Mammal Center in California, involves using a sedative dart, which enables our team to capture, disentangle, and treat seals. We work to minimize the suffering of seals, release them back to the ocean, and share our expertise with marine mammal rescue networks around the world. 

IFAW also promotes coexistence with seals by working with communities on Cape Cod to ensure that beachgoers can appreciate the animals from a safe distance, minimizing additional human impacts. We have distributed 100 informational seal signs to 14 towns and the Cape Cod National Seashore. Through greater awareness of seal behavior and habitat, the initiative aims to inspire community conversations around coexistence with wildlife rather than conflict.