Have you ever wondered about the differences between seals and sea lions? Whilst seals and sea lions look similar at first glance, there are a number of differences in their physical characteristics and behaviors, which we discuss below.
Seals and sea lions are two distinct families of marine mammals in the taxonomical suborder Pinnipedia, and are known as pinnipeds. This scientific name comes from the Latin terms pinna and ped, meaning feather-footed.
Sea lions together with fur seals are grouped together in the family Otariidae. True seals or earless seals are in the Phocidae family. Walruses are the third animal family, Odobenidae, in the Pinnipedia suborder.
Before we discuss the differences between seals and sea lions, it’s worth understanding the similarities between the two families:
Pinnipeds are semi-aquatic and split their time between the ocean and land habitats close to the shoreline. It’s thought that pinnipeds evolved from a terrestrial weasel-like ancestor (Phocidae) and a terrestrial bear-like ancestor (Otariida). These ancestors spent increasingly long periods in the water and eventually completely physically adapted to their marine habitat.
All seals and sea lions have short fur and whiskers (known as vibrissae) which work as sensors when hunting.
Their body shape is similar, with a sleek design and four flippers which they use to help them swim – and to varying degrees as aids to move around on land.
Seal vs sea lion – the physical differences
All sea lions have plain brown fur, ranging from tan to a dark chestnut brown. Seals come in a variety of colors and patterns, depending on their species. They can be anything from white to gray to a brownish-black, and are sometimes spotted.
Sea lions and fur seals (members of the eared seal family) have small, visible external ear flaps poking out from the side of their heads.
True seals completely lack external ears but simply have small ear holes on the side of their sleek heads you can see if you get close enough.
Flippers and mobility
There are significant differences in flipper length and use between sea lions and seals, which result in very different swimming techniques and land mobility:
Seals generally have furry, stubby, short front feet, which are actually thinly-webbed flippers with a claw on each toe. These compare to the long, skin-covered front flippers of the sea lion.
True seals’ hind flippers extend directly behind their bodies, and are not able to rotate. Sea lions and fur seals have longer hind flippers, along with a unique rotating hip bone that allows them to tuck their rear flippers under their body. This feature, along with their strength, lets them support their body weight on all four flippers and walk on land.
Both seals and sea lions are at home in the water, though due to their physical differences use different swimming techniques. In the water, seals use their back flippers to generate powerful side to side strokes like a fishtail. When sea lions swim they propel themselves by using their long front flippers like oars.
Seals move on land in a similar motion to a caterpillar, shifting their weight from front to back and wiggling around on their bellies with only limited use of their appendages.
Because of the size and strength of their flippers, and their ability to rotate their hind flippers toward the ground, sea lions are able to walk – and even jog – on all four flippers. It’s this ability to move well on land and in water that makes sea lions a favorite for water shows and displays at aquariums and marine parks.
Behavioral differences between seals and sea lions
Sea lions are very noisy animals – they tend to communicate and mark their territory using a combination of loud barks, bleats, growls, roars, and bellows. Seals on the other hand are much quieter, communicating with each other in soft grunts, moans, and hisses.
Seals are less social animals than their sea lion relatives. Seals spend more time in the water than sea lions, leading predominantly solitary lives, and only come ashore in groups once a year to mate. A group of seals is called a herd.
Sea lions are sociable animals and often found congregating in large groups on both land and sea – sometimes reaching upwards of 100,000 members. A group of sea lions in water is called a raft, or a colony when on land.
And that’s all for this round-up of sea lion vs seal. What do you think – any differences between these two aquatic animals surprise you? Or any differences we should add to this post? Please join in and let us know in the comments section below!