Skip to content

How can you tell the difference between seals and sea lions?

Seals vs. Sea lions - what's the difference?

Despite our name, Whale and Dolphin Conservation’s Marine Animal Rescue and Response team works with whales, dolphins, and seals! That’s right, we see four species of seals in Massachusetts and our team regularly receives reports of stranded seals in need of help.

Two species – harbor seals and grey seals – are residents, meaning we can see them along our coast year-round.

Two other species – harp seals and hooded seals – are wintertime visitors. They primarily reside in Canada, but make their way south to the United States when temperatures plummet and they have access to snow and ice 

All four species of seals (also called ‘pinnipeds) commonly seen in Massachusetts are members of the family Phocidae and are known as “true seals”. In fact, we only have phocids, or true seals, on the East Coast. On the West Coast of the US, you can find both seals and sea lions!

How can you tell the difference between seals and sea lions? We're here to help! 


Family: Phocidae

In the United States, found on both the East and West coasts.

Considered to be “earless”. Externally, they have ear holes, not ear flaps.

Day of the Seal 2023

Short flippers, mostly covered in fur.

Day of the Seal 2023 (1)

Ambulate, or move, by scooting on their bellies. They look awkward when on land, but their flippers are angled backwards, making them better swimmers.

Relatively quiet. Some howling or grunting, but don’t generally “bark”.


Family Otariidae

In the United States, only found on the West coast.

Considered to be “eared”, meaning they have external ear flaps.

Day of the Seal 2023 (2)

Long flippers, mostly lacking fur.

Day of the Seal 2023 (3)

Ambulate, or move, by walking on all four flippers. Sea lions rotate their flippers in towards their bodies and walk on their flippers that are padded by skin.

Sea lions are known for their barking noise. That classic “ARF! ARF! ARF!” sound is only made by sea lions, not seals.

WDC’s Marine Animal Rescue and Response team acts as first responders to marine mammals – including seals – who are in distress.

If you see a sick, injured, or deceased marine mammal from Weymouth to Plymouth, MA, be sure to report it to WDC’s hotline: 617-688-6872.  

Make a difference

Join our team  - no matter which way you choose, your commitment helps whales, dolphins, and our shared planet.

Save the whales, save the world.

Humpback whale spyhop


Adopt a whale and help us protect these amazing creatures.

Bottlenose dolphin calf breaching with its whole body out of the water


You can join our team and help us save whales and dolphins

Breaching North Atlantic right whale


Your gifts help us take action for whales and dolphins.

Orca spyhop


Support WDC by shopping for yourself or a friend.