Why do they flip sand?
With all that blubber, their bodies are designed to keep warm in cold water. Sand flipping helps them keep cool on land by acting as a sun screen. In addition, they sometimes can be seen flipping sand under stressful conditions.
Where are the big males?
The large males, those with the big noses that give elephant seals their name, are only on the beach in July-August to molt and in December-March for the birthing and breeding seasons. They spend most of the year foraging off the Aleutian Islands of Alaska.
Who are their predators?
Great white sharks and killer whales (Orcas) prey on elephant seals as well as other marine life. Great whites attack from below with most attacks occurring near the surface. If the bite is superficial, the seal may escape. Sometimes you can see e-seals with scars showing they had a near-miss encounter with a shark. Predation by orcas has been documented less frequently.
Are there sharks offshore?
Yes. Great white sharks are found in temperate coastal waters world-wide including off the Central Coast. Seals with fresh shark bites or shark bitten otter carcasses are seen sometimes along this coast but it isn’t believed that there is a large population of great whites in the area. At this time, they are not specifically targeting this rookery. Ano Nuevo, near Santa Cruz, has been a rookery since the early 50s and the sharks do seem to target it for part of the each year.
Are elephant seals here all year?
Yes, there are always some elephant seals here although they become very sparse in August and September. Individually, each seal is normally here twice a year for approximately one month each time with the exception of the adult males who are here for one month in summer and three months in December-March.
Why do adult males have a large nose?
The large nose is a secondary sexual characteristic indicating physical and sexual maturity. Large body size, large nose, and a deep booming voice sometimes serve to intimidate challengers thus avoiding energy depleting fights.
Are females pregnant for 11 months?
Technically yes. However, there is a delayed implantation of the embryo: the fertilized egg divides a few times and then just floats in the uterus. This allows the mother, who has lost over a third of her body weight feeding her recently delivered baby and herself with metabolized blubber, to regains some of that weight before the new fetus begins to grow. After three to four months, the blastocyst attaches to the uterine wall and begins growing again. Some experts believe that the hormones directing implantation are activated at the end of the molt. The eleven month gestation also serves to synchronize the births to the same time every year.
How long do they live?
Males can live to 14; females to 20. But only a few live that long. Only one in seven pups lives to 4 years old.
Why do they molt at the rookery?
Skin cells, of elephant seals or humans, take a real beating and need to be replaced. For humans, the process is continuous throughout the year - we shed and grow about nine pounds of skin cells each year. Because growing new skin cells requires circulating blood outside the blubber layer, elephant seals grow their new skin during a few weeks each year on the beach, where the loss of body heat is much less than would occur in the ocean.
What do they eat?
Females, who eat in the deep ocean, eat primarily squid. Males who forage over the continental shelf eat bottom dwelling species such as ratfish, hagfish, Pacific hake, rays, skates, and small sharks. Many of the things they eat are bioluminescent. They also swallow their prey whole and digest it in about six hours.
How much time do they spend at sea?
Adult and sub-adult males spend eight to nine months at sea; females and juveniles of both sexes spend ten months. Their dives last from twenty minutes to over an hour with only two to four minutes at the surface between dives. They do this their entire time at sea so they spend about 90% of their time at sea under water.
How deep do they dive?
The normally dive 1,000 to 2,000 feet but can go as deep as 5,000 feet. When they dive, they swim only for the first one hundred feet and coast for the remainder.
How do they stay down so long?
Elephant seals have a number of unusual adaptations which allow them to dive so deep and stay under so long. They must exhale before they dive to avoid the bends (an affliction caused by the absorption of gas by the cells at high pressure) so all the oxygen they have is that in the blood (in hemoglobin in the red blood cells) and in the muscle (in myoglobin). Their blood volume is twice that of a land mammal their size and that blood is 50% richer in hemoglobin.
In addition, they undergo significant physiological changes as part of their diving reflex. Their heart beat slows from 55-120 beats per minute to 4-15 beats per minute. They are able to divert the flow of blood from their extremities and restrict it to just their vital internal organs. These changes allow them to use less oxygen.
Do mothers have just one pup?
If twining occurs in northern elephant seals at all, it is very rare. It is documented in southern elephant seals, close relatives. As the mother loses one-third of her body weight while on the beach giving birth to a single pup and nursing it to 300 pounds, it is clear that twining would not be advantageous.
Do big males fight to the death?
Rarely. As beach dominance is established in December and during the breeding season in February, bulls often battle each other. These confrontations are often bloody but rarely result in serious injury. The neck and chest area of a large bull is protected by a calloused shield and a thick layer of blubber. Fights can last from just a few minutes to half an hour, depending upon how evenly matched the bulls are. On occasion, a broken jaw or blinded eye from such fights may eventually lead to death because they would impair foraging. Almost all mortality occurs at sea.
The younger males, often seen sparring either on the beach or in the shallow waters off shore, are learning how to fight but for them, as for other young male mammals, this is playing rather than fighting and animals are very seldom injured in this activity.
Why did they start coming to this rookery?
As the elephant seals rebounded from near-extinction, (see Introduction for details) they first established colonies on the islands offshore Baja California and California. As these rookeries became crowded, they began colonizing mainland beaches. They began coming here in 1990, populated initially by seals from San Miguel Island, San Nicolas Island, and Ano Nuevo. We still see seals at this rookery who were born elsewhere.
Elephant seals like large sandy beaches that do not have a significant human presence. They prefer south facing beaches with protection from northwest storms. The shallow waters protected from breakers provide areas where the weaned pups can learn to swim and older males can spar. The kelp forest not far off shore and the rapid drop-off of the sea bed protect the seals from predators.
Are they dead? Why do they just lie there?
People often think that seals on the beach are dead because they are not moving or breathing. They will often stop breathing and dramatically lower their heart rate – as they do routinely at sea – for periods of a few minutes to half an hour. That apnea and their general inactivity are ways of conserving energy. During the time they are on shore, which occurs only in the rookery, they are fasting and relying on their stored fat to meet their water and energy needs.
Do mothers meet up with their babies the next year?
Seals usually return to the beach where they were born but we don’t know if they recognize each other. It does not appear so.
How fast do they normally move in water?
It is estimated that they swim at speeds of 10 to 15 mph. En route to the feeding grounds, they cover around 60 miles a day, diving and foraging as they go.
How fast can they move on land?
While they seldom move rapidly at all on land, when they perceive a threat to themselves or the harem, they can move on soft sand faster than most humans.
Do big males hurt the babies?
It is very unusual for a big male to deliberately hurt a baby. However, babies can be accidentally injured or killed if they are in the way when a large male is defending his harem from another bull.
Do they go out in the ocean to eat?
They do not eat while at the rookery. Except for an occasional relocation within the rookery, and males sparring or fighting in the shallow water just off shore, they do not go in the water at all. They rely on metabolized blubber for energy and water.
How many females are in a harem?
The number of females in a harem varies according to the topography of the beach. There can be as few as 10 and as many as 50 surrounding an alpha male. He provides protection from the amorous attention of other males.
How old are they when they begin reproducing?
Males enter puberty around 4 years of age but they don’t reach their full physical growth until they are around 9. At that time they are big enough to become serious contenders for beach territory. Some males never win enough fights to ever be able to breed. Prime breeding age is between 9 and 12.
Females normally begin reproducing around age 4 although some begin as young as 2 or delay to as late as 6. They become physically mature and stop growing in length at age 6.
Do they come back to the same rookery each year?
It appears that elephant seals generally return to the beaches where they were born. However, overcrowding or failure to successfully wean a pup can prompt them to move to another rookery.
How big are they?
Large males are 14 to 16 feet in length and weigh between 3,000 and 5,000 pounds. Adult females are 9 to 12 feet in length and weigh between 900 and 1,800 pounds. Pups are 3 to 4 feet long and weigh 60 to 80 pounds at birth.
Where are the other rookeries?
All northern elephant seal rookeries are on the Pacific coast of North America – most on offshore islands but increasingly on the mainland – from Vancouver Island on the north to Baja California on the south. Most are along the California coast. The Piedras Blancas rookery has the easiest access for viewing. See a map showing the rookeries.
Do the Friends of the Elephant Seal help seals on the beach who are hurt or in trouble?
Not if the problem has not originated from human behavior. Seals in the rookery are allowed to live according to nature’s dictates without interference. It can be painful to watch animals in trouble without helping them but our objective is to respect the overall cycle of life in the wild. If a seal’s problem is caused by human interference the Marine Mammal Center is contacted. See a recent example of their work.