This month we wanted to switch things up! Let’s welcome our first otariid, the California sea lion. Don’t let the name fool you, this species ranges as far north as Alaska and as far south as Mexico. Come waddle your way through this post to find out more!
Are sea lions seals?
One of the biggest questions that comes about is aren’t they all just seals? The simple answer is, no! Seals or phocids are typically what scientists refer to as “true seals”, while sea lions or otariids are grouped as the eared seals. That’s not to mean seals don’t have ears! They just don’t have ear flaps. Instead, their ear is just a hole on the side of their head.
A true seal (left) vs a sea lion’s ears (right).
But this is not the only difference between seals and sea lions. They also show different behaviors. Sea lions are social butterflies, often seen in groups called rafts or herds. These groups can consist of up to 1,500 individuals. Seals on the contrary tend to be more solitary and spend the majority of their time in the water. Sea lions are also known to bark, whereas seals are much more quiet making soft grunts.
Sea Lions have skin on their front flippers and can rotate them in order to walk or waddle on land. Seals ungulate or flop on their bellies to get around on land. Seals’ front flippers also have fur and lots of claws. You can check out more about some of the seals we’ve highlighted: the Hawaiian monk seal and the leopard seal.
The art of thermoregulation
Sea lions rely on their flippers to keep themselves cool or warm up. Indeed, sea lions have found a way to regulate their body temperature or thermoregulate, by kicking their flippers up in the air! Their flippers do not have fur and are poorly insulated, compared to the rest of their body. In this part of their body, their blood vessels are really close to the surface of their skin. When they expose their flipper or flippers to the ocean surface, their blood vessels will dilate, thus helping the heat exchange between them. With this exchange, they either release excess heat or absorb it from their environment.
Population and ecosystem management: sea lions cullings
Sea lions can be found in abundance all along the west coast of the United States. Decades ago, fishermen and the general public hunted them for their fur or as pet food, thwarting their population. However, since the Marine Mammal Protection Act in 1972, sea lions’ populations have dramatically increased. With warming climates, California sea lions have started moving further north to find cooler waters and more food. Scientists have even witnessed sea lions eating Chinook salmon.
As of 2020, the United States approved a large cull of both California sea lions and the Stellar sea lions over a five-year period. Their plan is to mitigate sea lion consumption of these endangered fish (that Southern Killer Whales eat, for example). There is a lot of back and forth in the scientific community on this topic, and not everybody is on board. What do you think? Let us know in the comments below!
Thanks for Reading! Interested in more? Check out the links down below:
- What Would a British Columbia Seal and Sea Lion Cull Actually Entail?
- California Sea Lion
- Ocean Conservancy: Seal vs Sea Lion
Naomi Mathew is a PhD student at University of Louisiana at Lafayette. She works on bioacoustics in marine mammals from the Gulf of Mexico. She is the co-founder of Whale Scientists. You can read more about her here