Science
History
Art & Literature
GIS & Mapping
Library
History
Art & Literature
GIS & Mapping
Library
ChatRoom
Search
TrailHead
Base Camp
SEALS AND SEA LIONS
Seals and sea lions are pinnipeds, which means "fin- or feather-footed." They are mammals that have developed the ability to lead a double life, at once aquatic and terrestrial. Chilly ocean water does not faze them because their metabolism, along with a thick coat of fur lined with an insulating layer of fat, keep their internal temperature constant.
Pinnipeds are consummate divers. Among the different species, elephant seals have set the record for long dives at 77 minutes, reaching a maximum depth Of 1,000 meters. In addition to holding their breath, pinnipeds utilize a specially adapted circulatory system, which efficiently shuts down the flow of blood to their extremities so that the heart, lungs and brain will have enough oxygen. While diving, a seal's heartbeat may slow to half its normal rate, further enhancing its capacity to withstand the shortage of oxygen.
Though we often use the word seat as a catchall for these animals, a seal is not always a seal, and not all seals bark. Pinnipeds share many characteristics, but there are marked differences among the various species.
There are three families of pinnipeds: eared seats, true seals and walruses, which live only in Arctic waters. Sea lions and fur seals are eared seals. They have small external ear flaps and flexible hind * flippers that can be pulled up under their bodies to help them walk dog-like on land. The eared seals that live in the Channel Islands are the California sea lion and the northern fur seal. The Steller sea lion and the Guadalupe fur seal, eared seals that were once abundant in the channel, are seen only sporadically now and no longer breed here.
The cliched image of a circus "seal" balancing a beach ball on its smoothly tapered head is based on the California sea lion. The "arf arf arf' sound often attributed to cartoon seats is a version of the Califor, nia sea lion's staccato bark. Curious and playful with divers, these sea lions are easy to train and are commonly seen in zoos. The California sea lion, often found lounging on buoys or frolicking in the waves, is the most abundant pinniped in the channel. Some 80,000 of them live and breed here.
Northern fur seals are seen less frequently because they are fewer in number - less than 10,000 reportedly live in the channel - and when they go to sea, they tend to head for deep water offshore. They come ashore, or haul out, at Castle Rock and Adams' Cove on San Miguel Island. Northern fur seals are territorial animals that establish large harems, with males claiming an average of forty females. They habitually return to the same rookery to breed, usually the same place where they were born.
Steller sea lions are the most leonine of pin~ nipeds. These tawny, yellowish-brown animals defend their territory with a deep roar. They have broad faces and thick necks and are the largest of the eared seals in the Northern Hemisphere, with males weighing up to a ton. The Steller sea lion population is decreasing worldwide for undetermined reasons.
The Guadalupe fur seal, with its long, thin patrician nose, is now believed to be confined mostly to Isla de Guadalupe off the coast of Mexico. It once ranged from the Farallon Islands near San Francisco to the coast of Baia.
The harbor seal and the elephant seal, both residents of the channel, are earless or true seals. They have no external ear flaps and their bodies do not accommodate movement on land as well as the eared seats. Their hind flippers don't rotate under their bodies, and their small front flippers are even less helpful. In the water, they swim by moving the posterior part of their bodies back and forth like fish; on land, they flop along on their stomachs. How ever, what they lack in form and grace, they make up for with persistence, propelling themselves across the beach at astonishing rates when the need arises.
The speckled harbor seals are the least gregarious of these animals. They are wary of humans, and tend to congregate in smaller groups close to the water's edge. Individual harbor seals, wrinkling their bodies into uncomfortable-looking contortions, make striking photographic subjects. About 40,000 live in California waters.
The gargantuan elephant seals can weigh up to 6,000 pounds. The males have large, inflatable noses or trunks that they brandish menacingly during disputes with other males. These animals develop a pecking order in which the most aggressive males are rewarded with the greatest number of females.
The dramatic changes in pinniped censuses for the Santa Barbara Channel show just how easify a species can be affected by human activities. Northern fur seals, whose predictable habits made them easy prey for hunters, were once completely eliminated from San Miguel Island. In 1968, though, scientists discovered that they had recolonized the island.
Similarly, in 1938 only 13 elephant seals were counted on San Miguel Island; by 1978, 10,000 were counted there. Today, the population is thought to be larger than it ever was.
after hunting was outlawed by the International Fur Treaty of 19 11, most of the species have been able to bounce back. To further protect these vulnerable species, Congress passed the Marine Mammal Protection Act of 1972, which stipulates that marine mammals may not be harassed, hunted, captured or killed except by special permit from the Department of Commerce. According to the Act, harassment may be interpreted as any human activity that alters the behavior of the animals. Tampering with pinnipeds in any way, even with good intentions, is the wrong thing to do. If you are in the Santa Barbara Channel region and find a seal or sea lion that may be in distress, leave it alone and call the Marine Mammal Rehabilitation Center at (805) 687-3255.