1. Why are the sea lions here?
California sea lions have always frequented the San Francisco Bay, especially during the winter months when herring spawn in the bay. The Marine Mammal Center’s biologists believe that the California sea lions have chosen to haul out at PIER 39's K dock because there is plenty of food nearby in the bay and ocean, their natural predators (great white sharks and orcas) do not come in the Bay, and there is plenty of space. Also, the docks are easier to haul out on, more comfortable and protected from storms than a rocky beach. As the tide goes in and out, the docks move up and down, so the sea lions just keep sleeping rather then having to scramble up and down rocks with the tide!

Other docks along the Pacific Coast have had sea lions hauling out. When enough force is used to scare them away, they do not take up permanent residence.

2. When did they first come?
A few California sea lions began hauling out on K dock soon after the earthquake in the fall of 1989. By January 1990, the population had reached 150 and was increasing. Biologists believe that many PIER 39 individuals used to haul out at Seal Rock near the Cliff House. Some California sea lions still haul out at Seal Rock, but often there are none.

3. Didn't there used to be boats at K dock?
Yes, when the first sea lions arrived, half of the dock was filled with boats and half was overnight guest docking. The boat owners were not too happy about having to avoid sea lions in order to reach their boats. Initially there was some discussion about how to get rid of the animals, but nothing was done. The PIER 39 Marina contacted The Center to guide their decisions. Ultimately, for the safety of the boat owners, it was decided to leave the dock to the sea lions. Boat owners who owned dock slips were relocated elsewhere in the PIER 39 Marina. The weight of the sea lions, often thousands of pounds, caused K dock to submerge, become waterlogged and eventually fall apart. PIER 39 initially built twelve 10' x 12' floats, which were placed between the fingers of K dock. In the summer of 1995, the original K dock was removed, as it was a hazard to boats. More floats were moved in to replace the dock.

4. Do the sea lions stay here all year?
Yes and no. From late summer to late spring, 150-300 sea lions haul out here. In June and July, most of the sea lions head south to breeding grounds on the Channel Islands, but a few dozen have remained throughout the summer in recent years. In late July, non-breeding subadult males and females begin to migrate north again. Other breeding males travel north later. Some males migrate as far north as British Columbia, Canada, and Alaska.

5. How far away are the Channel Islands, and how long does it take the sea lions to get there?
The Channel Islands are 370 miles by land from San Francisco, off the coast of Santa Barbara. If a sea lion swam at maximum speed (25 mph), the trip would take it approximately 15 hours. However, sea lions don't swim at maximum speed; they take their time. It probably takes them a few days.

6. Do you feed them or take care of them in any way?
It is illegal in the U.S. to feed, harm or harass wild seals and sea lions, as well as all other marine mammals. The PIER 39 Marina staff hoses down the docks once a week, so that the smell of the sea lions does not drive away the tourists and neighboring boat owners. To do this, they use a boat pulling a small raft equipped with a compressor that pumps the bay water which is then sprayed on the docks. Additionally, The Center monitors sick and injured animals, rescuing them when possible.

7. Can they get out?
Yes, they are wild animals that come and go as they please. They swim out into the bay through the opening that the boats use at the North end of the pier.

8. Do the sea lions ever go onto the other docks at PIER 39?
The sea lions have pretty much learned that K dock is theirs and until 1995 rarely hauled out on other docks. Boat owners on other docks have been asked to discourage them from hauling out by using “herding boards” or large garbage cans on wheels to push the sea lions back into the water. In 1995, old dock sections of K dock, which sat lower in the water, were removed. At that time, a few California sea lions began hauling out on J dock. In the Spring of 1996, a large influx of juvenile California sea lions resulted in many them temporarily hauling out on J dock.

9. Are the bigger animals the males?
Yes, but actually about 85-95% of all the California sea lions at PIER 39 are males.

10. If these are mainly males, where are the females?
Most females typically live year-round at or near breeding grounds, which are primarily on the Channel Islands, off the coast of Santa Barbara, and on other islands South to Baja California and the Gulf of California in Mexico. Females have one pup each year. They stay with their new pup for about six to eight months, sometimes as long as a year. There are some females at PIER 39.

11. How old are the smallest ones?
The smallest sea lions are probably one to two years old.

12. Why are some of them dark in color and some of them lighter? Why are some of them different colors in different places? Are they molting?
Adult males are dark brown. Females' colors range from buff to light brown. Also, animals show individual variation -- that is, you could observe a light-colored adult male. Color also varies with the wetness of the fur. When sea lions are wet, they are dark and glossy. When they are dry, they look lighter brown. Some of the irregular coloring may be the result of water splashed on the coat of a dry animal or scars from old wounds. Small dollar-size round wounds are scars from a cookie cutter shark, which twists while it bites, leaving a circular wound. Larger bulls-eye looking wounds maybe from lampreys, a fish with a rasping sucker for a mouth.

Sea lions molt in late August and September. Molting generally starts at the head. While the old fur remains brown, new fur is cream or silvery-gray and turns brown within a couple of weeks.

13. Why are some of them in groups and some of them alone?
Sea lions are very gregarious social animals, so groups of sea lions are normal. They are positive thigmotactic animals, because they prefer to rest in close bodily contact with other animals. It is not unusual to see animals hauled out alone. There could be no reason, or it could be a large male that no other sea lion has attempted to join, or a sick or injured animal that prefers to be alone.

14. Do they swim in groups?
Sea lions do swim in groups at times. A group of sea lions swimming together or resting in the water is called a “raft.”

15. Do they bite?
Yes, they are wild animals that will bite if they feel cornered or threatened. If you were to approach one on the dock, he would most likely sit up, bark, move away, and ultimately jump into the water rather than try to attack you. However, older or injured sea lions may hold their ground and bite if you get too close.

16. Are they fighting?
At PIER 39 the California sea lions often "argue" over a haul out spot, who got there first and who is going to stay. Much of the shoving and some biting we see is between young males playing, or practicing behaviors or skills that they will need in the future when they are breeding males. Most serious fighting occurs between males defending their breeding territories, which would not be seen at PIER 39. However, fighting is rare, as it wastes energy needed for mating and can result in injury or death. Most "fights" are decided by vocalizations, size, posturing and neck and chest pushing.

17. How much time do they spend lying up on the docks compared to swimming around in the water?
You will observe some animals that will sleep in the same spot during your entire docent shift and longer. It is not unusual for them to sleep 8 to 12 hours. Sea lions are binge feeders, eating all they can when food is plentiful, and then hauling out and resting for long periods of time.

18. Why do some of them sit with their heads up in the air?
It is a comfortable way to sit and rest. It also may allow them to rest, while checking out areas behind them and staying aware of their surroundings.

19. Why do they stick their flippers up in the air?
Lifting up a flipper and flipper fanning are methods for cooling off (thermoregulation).

20. What kinds of diseases do sea lions get?
Because they are mammals, they get diseases similar to those found in humans, such as pneumonia, cancer, bacterial infections, and viral infections. For example, sea lions get leptospirosis, a bacterial infection similar to the one cats and dogs are vaccinated against. They are often infested by lung, heart and gastrointestinal parasites. Injuries include natural ones, inflicted by other sea lions or their predators. Human-caused injuries include entanglement in fishing gear (nets or hooks) or plastic debris, and wounds from boat propellers, bullets or buckshot.

21. Can we catch anything from sea lions? Can my dog catch anything?
Yes, it is possible that you or other mammals could catch something from a sea lion if they have a contagious disease and you touch them, their feces or are bitten. However, over the more than 30 years that marine mammals have been in captivity, very few cases have been recorded of humans catching something from marine mammals.

22. Does The Marine Mammal Center rescue sick or injured animals here?
Prior to 1995, The Center rescued seven sea lions at PIER 39's K dock. However, it is extremely difficult to rescue a sea lion off these docks. The docks are very unsteady, and when you approach the animals, they usually jump into the water. It's far easier to rescue an animal on a beach, where people with herding boards can surround the animal. Since the removal of the dock, it is extremely difficult to rescue sea lions on the floating docks. A specially trained Water Rescue Team has successfully rescued a few sea lions from K dock. Rescue attempts will be made on sick or injured sea lions that haul out on other nearby docks.

23. Can't you just shoot a tranquilizer dart at the animal you want to catch?
No, the sea lion would feel the dart, probably jump into the water, and then drown as the tranquilizer's effects take hold. Also, to properly anesthetize a sea lion, an injection of atropine must be administered 10-15 minutes before the anesthesia. Atropine helps maintain (increase) the heart rate and it dries up some of the fluid in the lungs. Without this preparatory injection, sea lions could drown in their own body fluids or die of other complications.

24. How successful is The Center at rehabilitating sea lions?
The average animal stays at The Center one to three months. Approximately 50% of the animals treated for more than 24 hours by The Center are released back to the wild.

25. What are the tags that you see on some of the animals?
Researchers and rehabilitation facilities like The Marine Mammal Center put on tags. An orange tag means that the animal has spent some time at a rehabilitation facility. The number series tells us if it was at The Center, Pacific Marine Mammal Center in Laguna Beach, or The Santa Barbara Rehabilitation Center or San Diego Sea World. Researchers put on other tag colors (red, green, or yellow). The color signifies the location where the animal was tagged. See “List of Tags/Marks Used for Research” in Section IV of this manual for further tag information.

26. Why are sea lions branded?
Some sea lions are permanently branded by researchers, who want to track them throughout their lives. A few branded sea lions can provide a wealth of information about range, behavior and life history. Tags are not as reliable as brands because, they may fall off or their numbers may wear off. Additionally, brands are easier to see than flipper tags.

27. How are they branded?
Numbers are put on with either a hot or cold brand. Hot brands are done with a heated metal number and cold brands are a copper number chilled with liquid nitrogen. With both procedures, sea lions must be held still. Hot brands take seconds to leave a mark, while cold brands may take about a minute. Hot brands are easier to do, but they destroy fur follicles and can cause deep damage. Cold brands are not as damaging, and the fur grows back white in color making the numbers clearly visible.

28. Do these procedures hurt them?
It’s impossible for us to know exactly what sensations animals feel, we can only observe their reactions and make an educated guess. While they do flinch or react to tagging and branding, they recover and heal very quickly. Tagging can be compared to getting an ear pierced. Branding is likely to be more painful, but again, the sensation would only be temporary.

29. How big are the babies when they are born?
They typically weigh 13-17 pounds and average two feet in length.

30. How long do the mothers nurse their pups?
Generally, pups will nurse for six months to a year. The length of nursing also depends on the area and specific conditions, such as ocean factors affecting fish availability. On the Galapagos Islands sea lion pups often nurse longer than a year, sometimes up to three years.

31. Can the babies swim right after they are born?
Pups cannot swim at birth. When they are about two to three weeks old, California sea lion pups start playing in the tidepools and shallow water, developing their swimming skills.

32. How old are sea lions when they first mate?
Males are sexually mature when they are about four to five years old, females when they are three to four years old. Males however, may not mate until they are 8-10 years old; when they are fully grown, more experienced, and can hold a breeding territory.

33. Do sea lions mate for life?
Sea lions do not mate for life. Females often mate with the male who is holding the breeding territory, where they give birth. She also may seek out another male she prefers. She can mate with more than one male in a breeding season. Dominant males that hold breeding territories typically mate with up to 40 females each breeding season. In subsequent seasons, other males may hold the territories.

34. How much do California sea lions weigh when they are fully grown, and how long does it take them to reach full size?
Males can grow up to about 1000 pounds; they reach full size after about 10 years. Females typically don't get much larger than about 350 pounds and may reach this size before their tenth year.

35. How long do California sea lions live?
In the wild, they live between 18 to 25 years; in captivity, they have been known to live longer.

36. What is the difference between a seal and a sea lion?
There are quite a few differences, some of which are easy to see. First, sea lions have small external ear flaps. Seals have no external flap; however, sometimes their ear hole is visible. Second, sea lions can rotate their rear flippers forward so that they can walk on land, using all four flippers. Seals cannot rotate their back flippers forward, so they drag their rear flippers and crawl on land. Also, sea lions have long wing-like front flippers with no claws, seals have short front flippers with claws.

37. Are these the same kind of seals/sea lions that they have in the circus?
Yes. When you see a trained “seal” at the circus, you are most likely seeing a trained sea lion. Sea lions are quick to learn new things, and can move more easily on land than seals can.

38. How can you tell the difference between males and females?
Subadult and adult males are usually dark brown. They have a thick neck and large head with a “bump” or sagittal crest on the top of their heads. The crest starts to appear when males are about five years old. Females are often light brown or buff in color and do not develop a sagittal crest. When the animals are young (five years or less) it's extremely difficult to tell females and males apart, unless they lie on their backs and you can distinguish their genital openings. Males have a penile opening between their umbilicus (belly button) and anus. Older males will have visible testicles. Females have no opening between their umbilicus and their vaginal/anal openings.

39. What do they eat?
Sea lions are opportunistic feeders, which means that they will eat whatever fish are abundant in the area at the time. In the San Francisco Bay during the winter, they eat mainly herring. At other times of the year, they feed more in the ocean on a variety of marine life, including rockfish, anchovies, hake, squid, octopus and smelt.

40. How frequently do they eat, and how much each day?
California sea lions eat when they are hungry and food is available. When it is available they binge feed, or eat all they can, because the fish could soon be gone. On the average they may eat 3 to 15 lbs. per day in the wild and may fast for several days at a time.

41. Where do they defecate?
Wherever they happen to be at the time--sometimes in the water, sometimes on the dock (which is why the PIER 39 Marina personnel clean the docks about once a week).

42. Do they get cold?
Generally, if sea lions and seals are healthy with a thick blubber layer, the cold will not affect them. Like humans, sea lions and seals are warm-blooded animals, so they must maintain their core body temperature. Their fur is made up mostly of guard hairs with very little insulating fur, so they depend primarily on their blubber for insulation. Also, their circulatory system is specially adapted to keep the warmth in. Arteries in their flippers, taking warm oxygenated blood from the heart, are surrounded by veins transporting cool oxygen-poor blood back to the heart. Any warmth that escapes from the arterial blood warms the cool venous blood, thus conserving body heat.

43. How deep can they swim? How fast?
California sea lions have been known to dive 1000 feet deep; however, most dives are less than 100 feet. Most often California sea lions swim a few miles per hour underwater. They can swim 25 mph in short bursts by “porpoising” or leaping out of the water to increase speed.

44. How long can California sea lions stay under water before having to come up for air?
Most dives are only a few minutes long, but California sea lions can stay under water 10 to 15 minutes.

45. How long can they stay out of the water?
California sea lions can stay out as long as they want. If they get too hot, however, they must return to the ocean to cool off. Also, since they eat fish, and fish are in the water, they need to go into the water in order to eat.

46. Are they nocturnal? When do they sleep? Eat?
They are most active during the day, however, they also can be active during the night. They eat all they can when fish are plentiful and then haul out and rest for long periods of time.

47. Can they see underwater? Do they see better above water or under it?
They can see clearly both above and underwater.

48. How smart are they?
By our standards, and comparing sea lions to other animals, they are considered extremely intelligent. Most everyone is familiar with the trained sea lions in aquarium shows that are trained to do a variety of complicated tasks, such as balancing balls “on their noses” (actually on their vibrissae), jumping through hoops, fetching objects and doing certain behaviors on command. Many people are not aware that researchers are studying sea lions' ability to learn a language, their memory skills, and ability to solve simple logic problems (e.g. A=B, B=C, therefore A=C). See the March 22, 1993 Time Magazine article, “Can Animals Think?”. However, our standards of judging “intelligence” should never be the final test. Sea lions are well adapted to their ocean environment; they can easily find food, escape predators, and sense what is going on in their underwater habitat. In addition, they have a complex social structure and modes of communication that we do not entirely understand.

49. Are the California sea lions considered an endangered species?
No, there are about 160,000 in the California population. Including California sea lions breeding in Mexico and the Galapagos sea lion, the total worldwide population is approximately 200,000. In the U.S., they are protected by the Marine Mammal Protection Act of 1972. The Steller sea lion, which also occurs in California and occasionally at PIER 39, is listed as threatened and endangered.

50. Who are their predators? Do they come into San Francisco Bay?
Great white sharks and orcas (killer whales) eat sea lions, but these animals are rarely sighted in San Francisco Bay. Other predators elsewhere include the hammerhead, blue, and bull sharks.

51. Fishermen do not like sea lions, do they? Are they allowed to shoot them?
Because sea lions like to eat fish and are curious and often unafraid of humans, they have been known to follow fishing boats, ruin fishing gear and steal the catch. Fishermen obviously do not like this and some do shoot sea lions. It is illegal for fishermen to shoot sea lions. Fishermen are required to try other methods to scare off the sea lions. Anyone caught illegally shooting sea lions will be tried in federal court.

Revised 8/99