©Five Star Whale Watching/ Andrew Lees. A Steller Sea Lion pokes its head out of the water in the Salish Sea.
Welcome to another Wildlife of the Week! Fortunately for us we have a lot of local marine species to talk about every week! As for this week, we’re going to discuss another very impressive Pinniped we often see on our coastlines. You may have spotted some varieties of pinnipeds before! Perhaps a Harbour seal or Sea Lion? Can anyone identify the species of Sea Lion in our photo here? It is the largest species of the “eared” and “fur” seals (not true seals).
You might notice in the image that this Steller (Northern or Alaskan) Sea Lion (Eumatopias jubatas) has some noticeable ear flaps. This is a major physical difference between true seals (e.g. Harbour seal) and all Sea Lions. Can anyone name some other differences? Learn more about the Steller Sea Lion below.
The Steller Sea Lion is a massive marine animal, and is one of the largest pinnipeds we get on our coast along with the Elephant Seal (true seal). The Steller Sea Lion weighs up to 2,500 pounds (~1100 kg) as males, whereas females are much smaller at approximately 800 pounds (~360 kg). The animal has a blonde/tan to red colored coat, their flippers typically darker than the rest of the body. This being said, they are fantastically fast, agile and graceful swimmers while in the water.
The species is sexually dimorphic, meaning males and females are easily told apart by physical characteristics. As mentioned, males range much larger in size but also have a more broad and robust body; their chest covered with thick, long hair.
Sea lions can be found throughout the North Pacific, distributed in temperate and subarctic regions. The Steller Sea Lion may be seen from southern California through to Alaska as well as northern Japan through to the Aleutian Islands and Bering Sea. It is believed that some mixing may exist between a Western and Eastern population of Steller Sea lions. As Sea lions require marine and land habitats, they tend to frequent coastlines but can occasionally be spotted in open sea regions.
As a predator, the Steller Sea Lion is a hunter with a diverse diet, capable of diving to great depths while hunting in-shore. Their menu includes an array of fish such as Salmon, Cod, Pollock, Mackerel, Herring and Rockfish, among others. The species will also prey on cephalopods such as squid and octopus. The Sea lion’s sharp canine teeth present clear evidence of an efficient and lethal predator for smaller marine prey.
As with many other pinnipeds, the Steller Sea Lion operates within strict breeding schedules during the year. “Rookeries” will be formed and usually a few dominant males will sire pups to large numbers of females, females reaching maturity between 3-5 years old. Births typically occur in spring and summer months, and pups will nurse with their mother for 1-3 years. They will not enter the water right away, but are still able to swim when born.
Steller Sea lions, among with other pinnipeds, depend on land and water both for survival. When pinnipeds “haul out” on shorelines or rocky outcroppings, they will rest, breed, give birth, thermoregulate (warm up) and moult when needed. This also provides some refuge from predators that prey on these animals themselves, such as Bigg’s Killer Whales.
If you are feeling like a Steller expert, check out some trivia below!
- Sea Lion adults may eat up to 6% of their body weight a day. (ANS: TRUE).
- Sea Lions swim and steer mostly with their large fore-flippers, as opposed to selas who use body undulations. (ANS: TRUE).
- Steller Sea Lions are also known as California Sea Lions. (ANS: FALSE. These are two species both frequently seen along the West Coast).
Where does the Steller Sea Lion get its name from?
Georg Willhelm Steller, who was a scientist, zoologist, physician and botanist in the 18th century.
Authored by: Alexa D./ Five Star Whale Watching
Check out some of our References to learn more!
- “Steller Sea Lion Biology.” Marine Mammal Research Unit, MMRU. University of British Columbia, Vancouver, Canada. http://mmru.ubc.ca/biology/steller-sea-lion-fast-facts/.
- “Steller Sea Lion.” NOAA Fisheries. National Oceanic and Atmospheric Administration. U.S. Department of Commerce. https://www.fisheries.noaa.gov/species/steller-sea-lion.