California sea lion facts for kids
Quick facts for kids California sea lionTemporal range: Pleistocene– Recent
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| Female Both in La Jolla, California |
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Zalophus
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californianus
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The California sea lion (Zalophus californianus) is a type of eared seal that lives along the western coast of North America. It is one of six kinds of sea lions. You can find them from southeast Alaska all the way to central Mexico, including the Gulf of California.
Male and female California sea lions look different. Males are bigger and have thicker necks. They also have a bump on their heads called a sagittal crest. These sea lions often rest on sandy or rocky beaches. They also like to hang out in places made by humans, like marinas and docks. California sea lions eat many kinds of fish and squid. Bigger animals like orcas (killer whales) and great white sharks sometimes hunt them.
California sea lions have a special way of breeding. From May to August, males set up areas called territories. They try to attract females to mate with them. Females can move freely between these territories. Mothers take care of their pups, nursing them between trips to find food. These sea lions make many sounds to talk to each other. Their most famous sound is a bark. Mothers and pups also use special calls to find each other. When it's not breeding season, California sea lions spend a lot of time in the ocean. But they come to shore to molt, which means shedding their old fur.
California sea lions are very smart animals. They can be trained to do many tasks. They also don't get scared of humans easily if they are used to them. Because they are so smart, you often see them in zoos, circuses, and oceanariums. The United States Navy Marine Mammal Program even trains them for special jobs. The International Union for Conservation of Nature (IUCN) says the California sea lion is a species of "Least Concern". This means there are lots of them. Sometimes, to protect fish, the US states of Oregon and Washington allow a certain number of sea lions to be removed each year.
Contents
What are California Sea Lions?
A French scientist named René Primevère Lesson first described the California sea lion in 1828. It belongs to a group of animals called Otariidae. This group includes other sea lions and fur seals. Otariids are also known as "eared seals." They are different from "true seals" because they have small ear flaps on the outside of their heads. They also have bigger front flippers and strong chest muscles.
The California sea lion is part of the Zalophus family. This name comes from Greek words meaning "intensive crest." This refers to the noticeable bump on the heads of male sea lions. For a long time, scientists thought the Galapagos sea lion and the extinct Japanese sea lion were just types of California sea lions. But in 2007, a study of their genes showed that they are all separate species. The California sea lion is most closely related to the Steller sea lion.
How Do They Look and Move?
Male and female California sea lions look different. This is called sexual dimorphism. Males can grow up to 2.7 meters (9 feet) long and weigh about 350 kilograms (770 pounds). Females are smaller, usually about 2.1 meters (7 feet) long and weighing around 100 kilograms (220 pounds). The heaviest male ever recorded weighed 660 kilograms (1,455 pounds)!
Young sea lions and females have light brown fur. After they shed their fur, they might look light gray or silver for a short time. Adult males are usually dark brown, but their fur can range from light brown to black. Some adult males might have light tan fur on their faces. Baby sea lions are born with black or dark brown fur. Adult males have strong necks, chests, and shoulders. They also have a noticeable crest on their heads with white hairs. Both males and females have long, narrow snouts.
California sea lions use their strong front flippers to swim. This helps them move smoothly through the water. They glide between each stroke of their flippers. Their flexible spines allow them to bend their necks far back. This helps them turn and stay streamlined underwater. When they are on land, they can turn their back flippers forward. This lets them walk on all four flippers. They move their front flippers from side to side. They also use their heads and necks a lot to move on land. California sea lions can swim around 10.8 kilometers per hour (6.7 mph). They can dive as deep as 274 meters (900 feet) and stay underwater for almost 10 minutes. Most dives are usually around 80 meters (260 feet) deep and last less than 3 minutes.
California sea lions can see colors, but only in the blue-green part of the light spectrum. This helps them see in their ocean home. They can hear very well underwater, from 0.4 to 32 kilohertz. They use their whiskers (vibrissae) to feel and detect movements in the water. Their whiskers are good at sensing things, even if they are not as specialized as some other seals.
Where Do They Live and What Do They Eat?
Their Home Range
California sea lions live along the western coast and islands of North America. Their range goes from southeast Alaska down to central Mexico. Scientists have found five different groups of California sea lions. These groups live in different areas, like the U.S. coast, Western Baja California, and three parts of the Gulf of California.
Most U.S. sea lions breed in the Channel Islands of California. But some breeding places are now found in northern California. The Baja California group breeds near Punta Eugenia. The Gulf of California groups live in different parts of the bay. Sometimes, sea lions wander far from their usual homes. They have been seen in places like the Commander Islands in the Pacific.
During breeding season, California sea lions gather on sandy and rocky beaches. On warm days, they stay close to the water. At night or when it's cool, they move further inland or to higher spots. Sea lions that are not breeding might gather at marinas, docks, or even navigation buoys. They can also live in fresh water for a while. For example, some have been seen near Bonneville Dam, far up the Columbia River. In 2004, a healthy sea lion was found on a road in Merced County, California. This was almost 160 kilometers (100 miles) from the ocean!
What Do They Eat?
California sea lions eat many kinds of seafood. They mostly eat squid and fish, and sometimes even clams. Some common foods include salmon, hake, Pacific whiting, anchovy, herring, and market squid. They usually look for food near coastlines, underwater shelves, and underwater mountains. They might also search along the ocean bottom.
Sea lions can eat alone or in groups. This depends on how much food is available. Sometimes, they work with other hunters like dolphins, porpoises, and seabirds. They do this when hunting large groups of fish. California sea lions sometimes follow dolphins and take advantage of their hunting efforts. Female sea lions usually find food 10 to 100 kilometers (6 to 60 miles) from shore. Males might go as far as 450 kilometers (280 miles) from shore when the water gets warmer. They have also learned to eat steelhead and salmon near dams. This happens where fish gather to pass through fish ladders.
Who Hunts Them?
Orcas (killer whales) and large sharks hunt California sea lions. In Monterey Bay, California sea lions are a common meal for orcas that eat mammals. Sea lions might react to a killer whale's fin and stay alert. California sea lions are also common prey for great white sharks. Some sea lions have scars from attacks by great white sharks and shortfin mako sharks. Sharks often attack sea lions by surprising them while they are resting on the surface. Sea lions that are attacked on their back end are more likely to survive and make it to shore.
Their Lives and Families
How They Have Babies and Raise Them
California sea lions have their babies between May and August. This is when they arrive at their breeding spots, called rookeries. When a male sets up his territory, he tries to stay there as long as possible to have more chances to mate. During this time, males do not eat. They use a thick layer of fat, called blubber, for energy. Bigger males have more blubber, so they can stay longer and defend their territory better. A male sea lion usually keeps his territory for about 27 days.
Males use special actions to protect their territory. These include loud sounds, shaking their heads, staring, and fake lunges. Since it can get very hot (over 30°C or 86°F) during this time, males need water in their territories. Some territories are even underwater, especially near steep cliffs. Sea lions that don't get a territory are either driven out to sea or gather on a nearby beach.
Female California sea lions have a 12-month cycle for having babies. They usually give birth in June or July. Females stay with their pups on shore for about 10 days and nurse them. After this, females go on trips to find food. These trips can last up to three days. Then they come back to nurse their pups for about a day. Pups left on shore often gather in groups to play and socialize.
When a mother comes back from a trip, she calls her pup with a special sound. The pup replies with its own sound. Mothers and pups can tell each other's calls apart from all the other sea lions. At first, mothers do most of the work to find their pups. But as pups get older, they help more in finding their mothers. Older pups might even go with their mothers on food-finding trips. Adult male sea lions do not help raise the pups. However, they have been seen helping to protect swimming pups from predators. Pups stop drinking milk around one year old, but some might continue for another year.
How They Talk to Each Other
California sea lions use many different sounds to communicate. Their most common sound is their unique bark. Males defending their territory are the loudest and bark almost constantly during breeding season. Sea lions bark very quickly when they are excited. The barks of males with territories and those without sound similar, but the territorial males have deeper barks. Males might bark when they are threatening other males or trying to attract females. The only other sound territorial males make is a "hoarse grunt" if a human startles them. Groups of non-breeding males also make this sound.
Female California sea lions are not as noisy. Their barks are high-pitched and shorter than males' barks. They use them when they are being aggressive. Other aggressive sounds females make include squeals, belches, and growls. The sound a female makes to call her pups is called a "pup-attraction call." It is described as "loud" and "brawling." Pups respond with a "mother-response call," which sounds similar. Pups also bleat or bark when they are playing or upset. California sea lions can also make sounds underwater. These include "whinny" sounds, barks, buzzings, and clicks.
What They Do When Not Breeding
Outside of breeding season, males travel to the northern parts of their range to find food. Females usually stay closer to the breeding areas. California sea lions can stay in the ocean for up to two weeks at a time. They dive continuously, coming to the surface to rest. They might travel alone or in groups while at sea. They come to shore to rest between each trip. Adult females and young sea lions shed their fur in autumn and winter. Adult males shed their fur in January and February. California sea lions in the Gulf of California do not travel far; they stay in the Gulf all year.
How Smart Are They?
Scientists have studied how smart California sea lions are. They found that these sea lions can understand how things are related, not just what they look like. For example, they can learn simple commands using a special sign language. In 2011, a sea lion named Ronan was filmed moving her head to the beat of music. This ability to move to a rhythm was thought to be only in humans and some birds before this.
Because they are so smart and can be trained, California sea lions are often seen in circuses and marine mammal parks. They can do tricks like balancing balls on their noses, climbing ladders, or honking horns. Trainers give them fish as a reward, which encourages them to perform. It can take a year to train a sea lion for a public show. But they have good memories and can still do a trick even after three months of not practicing. Some groups, like the Humane Society of the United States, believe that using sea lions for entertainment is not good. They say the tricks are just "exaggerated versions of their natural behaviors" and that the animals are not in their natural environment.
The U.S. Navy Marine Mammal Program uses California sea lions for special tasks. For example, they can be trained to find objects underwater or to detect divers. In places like the Persian Gulf, these animals can swim up to a diver near a ship and attach a special clamp with a rope to the diver's leg. Navy officials say the sea lions can do this very quickly. Some animal rights groups worry about the safety of these animals in such operations. However, the Navy says the sea lions are removed once their job is done.
Their Status and Protection
The IUCN says the California sea lion is a species of "Least Concern." This is because there are many of them, and their numbers are growing. There are an estimated 238,000–241,000 sea lions in the U.S. group. The group in Western Baja California has 75,000–85,000 sea lions. The Gulf of California group has about 31,393. Along the Pacific coast of the United States, there are so many California sea lions that they are almost at their maximum number for the area. However, the Gulf of California population dropped by 20% by 2008.
California sea lions can be harmed by people. Sometimes, they are killed if they cause problems for fishermen. They can also be caught in human-made trash or hunted illegally. Pollution from chemicals like DDT and PCB also threatens them. These chemicals build up in the ocean food chain.
In the United States, the California sea lion is protected by the federal Marine Mammal Protection Act (MMPA). This law was passed in 1972. It makes it illegal to hunt, kill, capture, or bother these animals. In 1994, the law was changed. It allowed for a small number of sea lions to be removed if they were eating endangered salmon. This could happen if their eating habits were greatly harming the salmon population. For example, at Ballard Locks and Bonneville Dam, up to 92 California sea lions can be removed each year for five years. Wildlife officials have tried to scare the sea lions away using loud sounds, rubber bullets, and bean bags, but these methods have not worked well.
Some people disagree with removing sea lions. They say that fishing and hydroelectric dams cause more harm to salmon than sea lions do. These animals also use human-made places like docks to rest. Many docks are not built to hold the weight of many sea lions. This can cause the docks to tilt or have other problems. Wildlife managers have tried different ways to manage the sea lions. Some cities have even rebuilt docks to be stronger.
Images for kids
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Shooting California sea lions, around the 1870s.
See also
In Spanish: Lobo marino de California para niños
