Archive | February, 2014

California Sea Lions are Here to Stay

California Sea Lion (Zalophus californius)

California Sea Lion (Zalophus californius)

California’s coastlines allow us to have access to an abundance of sea life. One of the most familiar visitors to our local beaches and islands are the California Sea Lions. These animals are the fastest of any sea lions or seals, swimming up to 25 miles per hour. While that is no match for predators like orcas and great white sharks who hunt the California sea lions, it gives them an advantage when hunting their own prey. These marine mammals like to feed on fish, squid, and shellfish. They have adapted to be able to slow their heart rates when they dive for fish, allowing them to dive deeper (as far as 1700 feet) and stay underwater longer.

These animals are commonly seen in large groups or colonies which can number in the hundreds. They range from the coasts of Alaska to Mexico in the Pacific. California sea lions are classified as pinnipeds because they have fin feet, which they use to scoot onto beaches and out of the water. These sea lions are also unique because they have ears, making them part of the otariid family. The ear flaps of a sea lion block water from entering the inner ear and causing infections. California sea lions hunt, swim, and migrate in the water, but come to rest on land where it is warm and where they can be safe from predators.

California sea lions spend more time ashore when they are molting, or shedding their fur, and when breeding. Male sea lions compete during breeding season (May to August) to establish a territory, and collect harems of females with which they breed. Females give birth on land after a nine-month gestation and pups will nurse for less than a year. Pups tend to huddle together on land while the females are out hunting for food. When she returns, each mother and pup can identify one another using distinct vocalizations, even among groups of hundreds of sea lions.

California sea lions sunning on buoy

California sea lions sunning on buoy

These animals are very dimorphic, meaning that there is a significant difference in appearance between males and females. While it may be difficult to identify from afar, the males can be two or three times the size of females. While a typical female is only around five feet long and weighs about 220 pounds, males can grow to be over seven feet long and weigh 860 pounds. Females also tend to have a lighter brown coat, while males are darker in color.

As a very intelligent species, California sea lions are often used in circuses and aquarium performances, and have been featured in films and television shows.They can be taught many behaviors, and are highly motivated by food. They are smart, playful, and have a dog-like bark which can be entertaining to some. They exhibit these same behaviors in the wild, and are popular among whale watchers and visitors to the California Coast. The Channel Islands are a popular hangout for these animals, and they are a staple on Fisherman’s Wharf in San Francisco.

Threats to this species are typical for marine mammals that share spaces with humans. they sometimes get tangled in fishing gear, or cause problems for fisherman by stealing fish, leading to the assumption that they are pests. Overpopulation of California sea lions is not an issue at this point, and scientists do not predict that it will become a problem. The population of California sea lions has been growing steadily since 1975. The species is very well adapted to its environment, and the population will remain healthy as long as there is a sufficient amount of food, and little intervention by humans.

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 Works Cited

California Sea Lion. The Marine mammal Center. http://www.marinemammalcenter.org/education/marine-mammal-information/pinnipeds/california-sea-lion/#.Uw4asyghwlJ Accessed February 21, 2014.

California Sea Lion. Animals. National Geographic. http://animals.nationalgeographic.com/animals/mammals/california-sea-lion/ Accessed February 21, 2014

The Season for Humpbacks Fast Approaches

It’s almost time for Humpback whale feeding season off the coast of California! Soon, whale watchers will begin seeing humpbacks migrating up the coast of California in search of food after a long winter of fasting and reproducing. The whales generally appear in April, but this warm California winter may mean an early migration. Humpback whales migrate to warmer waters off the coast of Mexico in the winter time in order to mate and give birth. During this time, they fast and survive off of their body’s fat stores. After breeding season, they migrate north to find small fish, plankton and krill. Humpback whales can be found in most seas and oceans of the world, and are known for their predictable migration patterns. These whales will travel about 16,000 miles every year!

Humpback whales (Megeptera novaeangliae) are baleen whales, meaning that instead of teeth, they have plates of dense bristles made of keratin that extend from their upper jaw. This is called a baleen. The whale’s primary means of getting food is to take huge gulps of water and then release the water through its mouth while any fish, krill, and plankton are filtered out by the baleen. The whales also have throat grooves that extend from under the navel. These grooves allow the whale’s body to expand and take in more water, allowing more food to be retained. A humpback whale can eat up to 5,500 pounds of food a day!

Adult humpback whales can grow in size anywhere from 48 to 62.5 feet long, and can weigh up to 80,000 pounds, with the females being larger than the males. It takes a young humpback ten years to reach its full size and maturity, and adults generally live to be 45 to 50 years old. Humpback calves are born at about 2,000 pounds and mothers will nurse their young for a year before the calf is ready to forage for food on its own. The whales tend to stay in loosely gregarious pods, and males are known for their long, complex songs. Research is still being conducted on the songs of male humpbacks, but we know that they can go on for hours and can be heard from long distances. Scientists believe that the songs are used for communication and possibly to attract mates.

Whale watchers are fond of humpback whales because they are known to be somewhat interested in boats and people, and can put on quite a show. Each humpback whale is easily identifiable by its unique fluke pattern. The underside of a humpback’s tail is usually spotted with white markings, unique to each individual whale, like a fingerprint. This makes it easy for whale watchers and researches to spot the same whales year after year, and document their migrations and behavior. Many whales express interest in passing boats by spyhopping, which allows them to stick their heads out of the water and investigate what is going on at the surface. Humpback whales can also be observed breaching, or jumping completely out of the water. Scientists think this may help them to knock parasites off of their skin, but it may be a social behavior that whales do just for fun. Fin slapping is another behavior observed by whale watchers, where the whales will slap their pectoral fins down hard on the surface of the water. Lobtailing is a hard slap with the tail fin. This may be a hunting technique in order to create noise and vibrations under water to scare fish. When fish are in danger they will group tightly together, which allows whales to gulp large quantities all at once.

Unfortunately, there are several serious threats to this species of marine mammal. Because it is a large whale with lots of meat and fat to offer, the humpback whale is a target for the whaling industry. Although it is a protected species, some illegal whaling still takes place. It is estimated that nearly 90% of the humpback population was wiped out prior to the 1966 ban on whaling. The population has since stabilized, but still faces many threats caused by humans, such as pollution, ship strikes and becoming entangled in fishing nets.

If you have the opportunity this year to view humpback whales, please do so. Many whale watching excursions seek out these animals for passengers to see because they like to show off for spectators and photographers. If you have already seen these acrobatic giants, you may learn something new about the fascinating underwater lives of marine mammals.

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Works Cited

Humpback Whales on the Central California Coast. Big Sur Chamber of Commerce. http://www.bigsurcalifornia.org/whalehumpback.html. Accessed 2/9/14

Humpback Whale. Animals. National Geographic. http://animals.nationalgeographic.com/animals/mammals/humpback-whale. Accessed 2/10/14

Humpback Whale. Enchanted Learning. http://www.enchantedlearning.com/subjects/whales/species/Humpbackwhale.shtml. Accessed 2/10/14