California Sea Lion

Sea lions are aquatic carnivores that feed on over 50 fish species and cephalopods. Their primary diet includes squid, octopus, and small schooling fish like herring and anchovies.

At the Zoo, sea lions are provided with Atlantic herring, capelin, and squid.

Sea lions receive all of the water they need from the fish they eat. However, the fish provided by the Zoo is flash-frozen after being caught, which can reduce its water content. To help make up for this loss and to offer enrichment, the sea lions also eat unflavored gelatin without any additives.

Their migratory range spans the western coast of North America, from British Columbia to the southern tip of Baja California, Mexico.

Sea lions are often found along the rocky and sandy beaches of coastal islands and the shorelines of the mainland. They often frequent sandbars, sheltered coves, tide pools, and even man-made structures like piers, jetties, and buoys. 

Sea lions are prey for orca whales and great white sharks.

The most significant threats to California sea lions are becoming tangled in fishing nets or ingesting trash in the ocean as they search for food, which can be fatal. As top predators in their environment, sea lions can gather harmful pollutants and microplastics in their bodies. This buildup can lead to toxic effects and even death.

Males are large and have a darker brown coat with lighter shades on their bellies and sides. They have a noticeable bony crest at the back of their skull, called a sagittal crest, which often has white fur when fully grown. On the other hand, adult females are smaller and have a tan coat. Sea lion pups are born with a blackish-brown coat, which changes to a lighter brown after about a month. They shed this juvenile coat after four to five months, eventually getting their adult fur. All sea lions have black flippers covered with short stubble.

Sea lions are amazing swimmers that use their front flippers to glide through the water. They can reach quick speeds of up to 25 miles per hour for short distances, but usually swim at a steady pace of six to ten miles per hour. When diving, sea lions can go as deep as 1,000 feet and hold their breath for about 10 minutes. However, most of their dives are shallower, typically between 50 to 200 feet, and last around three minutes. To help during deeper dives, sea lions can slow their heart rate and have special adaptations to avoid oxygen deficiency. On land, their back flippers can move independently and rotate under their body, allowing them to maintain great balance and move around easily.

California sea lions are well adapted to their environment. Their thick layer of blubber keeps them warm and helps them float, especially during breeding season, when males need extra energy when fasting. Sea lions can regulate their body temperature by holding their pectoral flippers in the air to release or absorb heat while in the water.

Sea lions can see well both above and below water. They have a special membrane in their eye called the tapetum lucidum, which helps them see in the dark, much like cats. On land, a protective membrane moves across their eye to wipe away sand and debris. They can also adjust to changes in light and are thought to be able to see different colors, especially within the blue-green range.

During the breeding season, male sea lions create and protect their territories, staying within these areas for several weeks, even when they need to eat. If they leave their territory to find food, they must set up their boundaries again, which could mean missing out on breeding opportunities. The peak breeding season occurs in the summer.

After an 11-month pregnancy, most sea lion pups are born in June or July, weighing about 13 to 20 pounds. Mothers stay on shore with their pups for about a week before going on their first foraging trip, which typically lasts two to three days. After feeding themselves, they return to care for their pups at the rookery for an additional one to two days. Nursing can last six months to a year, depending on prey availability.  

Once sea lion pups are fully weaned and learn the skills they need from their mother, they become independent and usually reach breeding age at around 4 to 5 years old. 

California sea lions are very vocal animals and can make a variety of sounds both in and out of the water, like barks, growls, and grunts. When it's breeding season, male sea lions bark a lot to establish their territories. Once their territories are secured, they mainly bark to maintain and defend them.

Females have a specific vocalization they use to locate their pups when returning to the rookery after feeding. They make a loud trumpeting sound, which makes their pups respond with a bleat. This exchange continues until they find each other. The mother and pup also use their sense of smell and sight to recognize one another.

Female sea lions can become very aggressive before and after giving birth. Their warning sounds change from a bark to a loud squeal, then to a stronger belch and an irregular growl.

Sea lions can be seen jumping out of the water, or porpoising, likely to increase their swimming speed. They are very social animals that can be seen resting together on land or floating in groups, called rafts, on the surface of the ocean.

Reducing the amount of single-use plastics you use can benefit sea lions. Much of these items end up in the oceans or other waterways, where they never fully break down, often entangling or being swallowed by ocean animals.