Sea Lion Size Comparison: Just How Big Do These Animals Get?

Written by Adam Segaller
Published: December 5, 2023
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Big, majestic, whiskered aquatic animals that are graceful in the water and awkwardly floppy on land, sea lions are from the pinniped family and live in climates ranging from subarctic to tropical. Living up to 30 years, these large, slick-skinned, gray and flippered mammals regularly grow to larger-than-a-large-human size. With six different species of sea lion and difference in sizes between males and females, there is a range of sizes in which sea lions come. From the relatively wee Galapagos Sea Lion to the scale-breaking Northern Sea Lion, let’s get a sense of sea lions’ size comparison as well as just how big these animals can get.

Wild Male Steller Sea Lion

All sea lions are mammals who live in the water with some time spent on land.

©NatureDiver/Shutterstock.com

What All Sea Lions Have In Common

All sea lions are mammals who live in the water with some time spent on land. They can all walk on all fours — those “fours” being flippers, with a longer pair in front. The back pair can rotate in a way that helps them propel their heavy bodies forward when on land. Sea lions always have big bellies and chests, short, thick and hairy coats, and whiskers. Those coats cover waterproof skin over a thick blubbery layer designed to provide warmth in the ocean’s cold climes. Their life spans are typically 20 to 30 years.

Sea lions are all big eaters, who can eat up to 8% of their own body weight at each meal. They can swim at a speed of up to 30 knots (around 35 miles per hour, or twice the max speed of a rental scooter!).

Often confused with seals, sea lions are distinctly identifiable by their ears: Where seals’ ears are just a tiny slit on the side of the head, sea lions have small flaps over the opening of each ear.

Different Kinds of Sea Lions

From California to the Galapagos to the Arctic, sea lions have evolved and adapted to their environment, finally resulting in six distinct species — seven if you count the extinct Japanese Sea Lion. That leaves the Australian Sea Lion, the California Sea Lion, the Galapagos Sea Lion, Hooker’s or the New Zealand Sea Lion, the South American Sea Lion, and Steller’s or the Northern Sea Lion.

The Smallest Sea Lions

The smallest Sea Lion is the Galapagos, because they live exclusively in the Galapagos Islands, an archipelago in the Eastern Pacific Ocean off the coast of Ecuador in South America. Male sea lions grow larger than females do; so female Galapagos sea lions are the smallest of the smallest. Even so, they’re still heavy, dense creatures! Even a female Galapagos sea lion can grow to an adult weight of around 175 pounds. And keep in mind, we’re only going to get bigger from here…

Mid-Sized Sea Lions

All right, so an adult female Galapagos sea lion is still in the range of weight a human might reach: the average range of a person’s weight is around 130 to 180 pounds. But as soon as we get to the middle range of sea lion size, sea lions become way bigger than humans. Consider that an average-sized male California sea lion is about eight feet long — and weighs over 650 pounds. (The females grow to a somewhat less gigantic, but still gigantic, six feet and 220 pounds.)

If you had to pick a land mammal closely evolutionarily related to the sea lion, bears would be a good choice — they share common ancestors in the prehistoric era. And when you look at the relative size of these hairy beasts, you might see another commonality. For our money, this makes it even more impressive that sea lions can propel all that body weight in water so gracefully.

sea lion

The California Sea Lion is at least risk of extinction, unlike the Australian, Galapagos and New Zealand Sea Lion.

©Daniel Avram/Shutterstock.com

The Biggest Sea Lions

The Steller’s Sea Lion, or Northern Sea Lion, is the true whopper of the sea lion family. Perhaps having grown so large to cope with the frozen temperatures in which they often live, these sea lions regularly grow to a weight surpassing 2,000 pounds! And they wear it well at lengths of over 10 feet.

Sea Lions: Large, But Endangered

The International Union for the Conservation of Nature lists three species of sea lions as endangered. These are the Australian Sea Lion, the Galapagos Sea Lion, and the New Zealand Sea Lion. The Steller Sea Lion, its superlative size notwithstanding, is listed as Near Threatened.

Not all species of sea lions are in such dire straits: the South American and Californian Sea Lion are both listed as being of least concern in terms of their risk of extinction.

The photo featured at the top of this post is © Goldilock Project/Shutterstock.com


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About the Author

Adam is a writer at A-Z Animals, where his focus is on dogs, states and history. A graduate of the University of Virginia, he now calls California home.

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