While sailing along the Pacific coast in the 1800s, a whale and seal hunter named Charles Scammon reported seeing northern elephant seals from Baja California in Mexico to Point Reyes in California. Sharing the fate of many of the oceans' great whales, the elephant seals were hunted to the brink of extinction for their oil-rich blubber. One bull elephant seal would yield nearly 25 gallons of oil. Though we don't know exactly how many northern elephant seals were alive before 1900 CE, it has been estimated that fewer than 1,000 northern elephant seals existed by 1910. In 1922, the Mexican government banned hunting, followed shortly thereafter by the United States government. Since then, the population of northern elephant seals has recovered at an average rate of six percent per year. Thanks to government protection and the seals' distant lives at sea, the worldwide population had grown to an estimated 210,000 to 239,000 seals by 2010. (Lowry et al., 2014) After being absent for more than 150 years, elephant seals returned to the sandy beaches on the rocky Point Reyes Headlands in the early 1970s. In 1981, the first breeding pair was discovered near Chimney Rock. Between 1988 and 1993, the population grew at a dramatic annual average rate of 32%. Since 1993, the average growth rate has slowed to 8–9% per year. When severe storms have occurred—such as in 1992, 1994, and 1998—many pups were killed. During the El Niño winter of 1998, storms and high tides washed away approximately 85% of the 350 young pups before they had learned to swim. Nevertheless, the Point Reyes elephant seal population has grown with each passing decade and is estimated to be approximately 4,000 seals, as of 2022. Fanning out from their initial secluded spot, the seals have expanded to popular beaches, causing concern for both their safety and that of their human visitors. Competition for HabitatSensitive resources such as birds and plants are also affected by elephant seals. The western snowy plover, a Federally threatened species under the Endangered Species Act, breeds on few California beaches. Loss of habitat to beachfront development and human recreation has forced elephant seals and plovers to compete for limited protected space. Also, rare plants native to coastal dunes are potentially at risk. Elephant seals and their curious human visitors may physically crush plants that are struggling to remain alive. The park's task is to balance the expansion of the elephant seal colony while providing for the health of other species. To manage this balance, the park will continue its docent program, which provides visitors with on-site information and safety messages at the overlooks. To anticipate where the elephant seals might expand to next, researchers will attempt to discover why seals prefer to breed on some beaches and not others. This information will allow the park to make responsible choices about appropriate beach use by people, pets, and wildlife. The Secret Lives of Elephant SealsNorthern elephant seals are mysterious and unique creatures. Elephant seals range from Mexico to Alaska in search of food and spend 80 percent of their life in the open sea. Not only do they spend most of their life in the ocean, 90 percent of that time is spent underwater: eating, sleeping, digesting, and traveling. They are built to survive continuous dives to depths that would squeeze the life out of any other mammal. The average dive reaches 1,000 to 2,000 feet, lasts close to half an hour and is followed by only 3–5 minutes at the surface to breathe. Imagine being able to live in such extremes! Why do they dive so deep? The oceans are full of food for millions of animals, but relatively few feed at the depths elephant seals prefer. As a result, they face little competition for food. Feeding in almost total darkness, elephant seals use their large eyes and the bioluminescence of some prey, such as octopus and squid, to find food where other predators would not even be able to see. They may use their stiff yet sensitive three to eight inch long whiskers to "feel" some food, such as Pacific hake, skates, rays, shrimp, small sharks and crabs. 
What allows such deep diving? Pressure increases as seals go deeper into the ocean. As they dive, outside pressure compresses the air in their bodies. Elephant seals differ from humans in that when they dive, they carry all the oxygen they need in their blood rather than their lungs. Before diving, elephant seals exhale; collapsing their lungs so there is little air to be compressed. As they dive, the seals fat is also compressed so that the animal loses its buoyancy and sinks, allowing it to achieve great depth with little effort. Elephant seals prolong their dives by reducing their heart rate. A seal resting on land has a heart rate of 55–120 beats per minute, but when it dives, the heart slows to 4–15 beats per minute. The seal maintains normal blood pressure by decreasing the blood supply to its extremities, allowing the blood to flow primarily to the vital organs and the brain. This also helps the seal conserve body heat when down in the cold ocean depths. During semi-annual migrations, adult males and females are not only thousands of miles apart, but they have different feeding patterns. Males return to the same feeding areas off the Aleutian Islands each year, while females feed in the open ocean of the northeast Pacific. To complete both round-trips, females journey over 11,000 miles, males 13,000 miles. Males dive deeply and repeatedly for food. After about three weeks, they have eaten so much that their dive pattern changes to a flat-bottom dive, following the bottom contours as they rest and digest. Females also dive deeply and repeatedly, but they go deeper during the daytime than at night. Although their locations and diving patterns differ, both sexes dive repeatedly for four to five months during summer and fall. Research suggests that elephant seals forage continuously during their migrations and, furthermore, they don't sleep! They may take "cat-naps" when they dive, as their heart rate slows, making only brief, infrequent surface appearances. This pattern, and the incredible amount of time spent below the surface, explains why so few of them have been seen in the open ocean despite their rapidly growing population. For more information, check out our Elephant Seals Resource Newsletter (1,284 KB PDF - Adobe® Acrobat Reader® may be needed to view PDF documents). Point Reyes National Seashore is one of the few places on the Pacific Coast where northern elephant seals may be observed and studied. Their semi-annual sojourns to the shores of Point Reyes provide a unique opportunity to glimpse the lives and behaviors of these elusive ocean giants. The Elephant Seal Overlook near Chimney Rock is a great place for viewing elephant seals and discovering for yourself the secrets of these wild wonders of the deep! Check out our Weekly Elephant Seal updates to learn the latest news. Even more information can be found on the Pacific Coast Science and Learning Center's Elephant Seals webpage. How You Can Help the Elephant SealA number of organizations are concerned about the welfare of elephant seals in California and throughout the U.S.A. They provide a range of services, from educational materials to studying the animals' needs. You can get involved in a number of ways, among which are the following:
Interactive Story MapMultimediaTranscript
[MUSIC PLAYING] I think it's fair to say that Point Reyes is like pinniped heaven. As you can see from the beaches out there it, is a magnet for elephant seals, for harbor seals. It's just a natural haven, a natural sanctuary for these animals to come and rest, and reproduce, and recharge.
Out of all the pinnipeds in Point Reyes, one of the most charismatic, also the one that draws the most visitors is the elephant seal, just because there's so much story to them and they're just so much more active. They really put on a show, basically, with all of the fighting, and the interactions, and the pups. There's just a lot more to see. Elephant seals used to prehistorically be in California. So they were hunted almost to extinction. They're a great story of a species to recover with simple protection by places like national parks. Right now, in Point Reyes is their breeding season, which is during the winter. And so a lot is going on at that time. Males show up first. They compete with each other to figure out who's going to be the alpha. Then the females show up. Within a few days, they give birth. They nurse their pups for about 28 days on average. Then they're going to wean their pup, and then they're going to leave. But while that's all going on, the males are still constantly fighting each other. We study elephant seals and we monitor them. That means we study them year after year. And we put that data together so we can understand what's the trend of the population. Is it going up? Is it going down? Is it flat? To do the surveys of elephant seals in Point Reyes, we have two strategies. The easiest way to count the seals is actually to be up above, so to be up on cliffs. And we're using a spotting scope. And that gives us a much wider, more on top view of the animals. And so we'll use spotting scopes or binoculars. But sometimes we have areas where we just can't really get that kind of a viewpoint. And so we actually have to be on the beach with the animals. And we're really trying to do accurate counting. And we want to make sure we don't miss, and especially the pups that might be hiding behind the females. Another part of our monitoring process is tagging the weaned pup. And a weaned pup is what the word sounds like, a pup that has been weaned, so the mom is no longer nursing it. And for now it's off on its own, away from the harem. And so we're going to go and try to apply a flipper tag. And we wait for that to happen because we don't want to interrupt that bonding process or the nursing process between the mom and her pup. The best way to tag an elephant seal is to sneak up on one that's asleep and do a real quick punch into their flipper. Most of the time, they do react. It's just like if you were asleep and someone came up and pinched you. You would probably react. So it wakes them up. They might squeal a little bit because of their surprise. But usually they calm down within a few seconds or a few minutes after it happens. Five, 10 minutes later, most the time they're back asleep. Well, we went through that question. Why tag elephant seals? And we decided that we would tag them because it helps us to understand the exchange between the other colonies because we share our data with the other researchers at the other colonies in central California. And by doing so, we understand better the whole population of central California, which is the leading edge of growth for elephant seals. Tags can tell you about survivorship. You know the age of the animal, you know the location where it was born. They can tell you a lot of things. Most of the tagged animals we see are from Point Reyes. That tells us that it's a more stable population and animals are coming back to Point Reyes to breed. Elephant seals definitely need a safe place to come raise their pups. The pups can't really swim at birth for at least the few first weeks. So they need an area on a beach where they're not going to get washed out by waves. They need the safety of the sand, and they need the safety from people. So we close the beaches to people because people are dangerous to elephant seals and elephant seals are dangerous to people. If people disturb elephant seals, that can cause them to displace pups and females and males. And if people get too close to females, they can attack them and bite them. So it's best for both to have these beaches protected. As biologists, we do need to go into the colony where most people can't access. But we are trained to recognize for animal behavior. Also, we know how to act around them. So we know when to keep our distance and when we can maybe get a little bit closer. So we're trained really to make sure that we are not causing any disturbance that is not necessary. [MUSIC PLAYING] Marine ecosystems are important, and it's important for us to understand them better because it's hard to study them. And so we may know a bit about the surface of the ocean, but not much about the deep ocean. And elephant seals are the bridge between the surface and the deep ocean because they dive so deep. And when somebody goes to the beach, they just see the ocean's surface. They don't understand the depth of it. When you look at an elephant seal, and you think this animal's dove a mile under water, what is it seeing down there? How can it stay down there for an hour and a half? So understanding the ecology of national parks is vital to what we do. It's vital to what I do as a park manager. When I'm making decisions about how we're going to manage the park, how we plan for the future, how we insure these animals are here for future generations to enjoy, how we protect people today, understanding what's going on the ground with the wildlife is absolutely critical. And that's when inventory and monitoring does for us. The inventory and monitoring program is not a new concept. It evolved over 20 plus years in the Park Service. But we're the leaders of many agencies in implementing it. And the data that we're getting back is already being used to help us to be better stewards. It's a fantastic program, it's a model for the nation, and we do it with a little money and a lot of leverage with partners, and friends, and citizen scientists, and volunteers. Everybody's a steward.
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Point Reyes National Seashore is "like pinniped heaven." Out of all of the pinniped species that use the park's coastline, elephant seals are the most charismatic. Discover how and why National Park Service scientists study the elephant seals at Point Reyes year after year.
KQED's Quest ProgramInto the Deep with Elephant Seals - initially aired on May 4, 2011 Photo GalleriesRead More about the Northern Elephant Seal at Point ReyesScience & Research Project SummariesFrom 2006 to 2018, Point Reyes National Seashore and Pacific Coast Science and Learning Center (PCSLC) staff and communication interns assisted scientists conducting research through the PCSLC and the San Francisco Bay Area Inventory & Monitoring Network to produce a series of Resource Project Summaries, two of which was about elephant seals. These one- to two-page summaries provide information about the questions that the researchers hoped to answer, details about the project and methods, and the results of the research projects in a way that is easy to understand.
ReferencesLowry, M.S., R. Condit, B.Hatfield, S.G. Allen, R. Berger, P.A. Morris, B.J. Le Boeuf, and J. Reiter. 2014. Abundance, Distribution, and Population Growth of the Northern Elephant Seal (Mirounga angustirostris) in the United States from 1991 to 2010. Aquatic Mammals. Vol. 40(1):20–31. Available at http://ctfs.si.edu/Public/pdfs/LowryConditEtAl_AqMamm2014.pdf (accessed 29 April 2022). |
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Last updated: September 17, 2024