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Año Nuevo Review Test yourself on what you know about elephant seals at Año Nuevo! 1 Good Luck!

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Presentation on theme: "Año Nuevo Review Test yourself on what you know about elephant seals at Año Nuevo! 1 Good Luck!"— Presentation transcript:

1 Año Nuevo Review Test yourself on what you know about elephant seals at Año Nuevo! 1 Good Luck!

2 Adapted from our friends at Friends of the Elephant Seal Thanks! 2

3 Instructions Begin slide show (option on upper tool bar) Each slide will ask a question. When you have the answer in mind advance the slide with the space bar or arrow key. In some cases this will give you a photo hint whether you need it or not. Advance the slide again to see the answer. Have fun! 3

4 Elephant Seals are pinnipeds. What does pinniped refer to? The word “Pinniped” is derived from the Latin word for “feather or fin- footed”, referring to the flippers. 4

5 Can you name some other pinnipeds? California Sea Lions…………. Stellar Sea Lions.. Harbor Seals……………….. Fur Seals…

6 Sea Lions have small, tightly curled, external ear flaps. They also have powerful foreflippers used for swimming. Their rear flippers can be rotated forward allowing them to lift their bodies and walk using all four flippers. Elephant seals and true seals have small ear holes and their foreflippers are much shorter making their movement on land appear awkward. The Elephant Seal is a True Seal. What is the difference between a “True Seal” and a California Sea Lion? Vs. 6

7 Are Elephant Seals Endangered? No. In 2010, the population estimate was around 166,000 seals. However, this was not always the case. 7

8 In the 1880’s, Northern Elephant Seals were nearly extinct. Why was this? Due to harvesting by whalers and sealers for their blubber. The oil obtained from elephant seals was used for lamps, lubrication, and in the manufacture of paint, soap, and candles. 8

9 A small colony of Elephant Seals, between 20 and 100 individuals, survived the ravages of the hunts. Where did this small colony come from? Guadalupe Island, off Baja California in Mexico. 9

10 Because all of the Northern Elephant Seals alive today came from that one small group that survived the seal hunts, what do they lack? Genetic Diversity – There is concern that low genetic variability will compromise their resistance to new diseases. 10

11 Piedras Blancas Año Nuevo Point Reyes Race Rocks, Vancouver Island Most of the North American Elephant Seals’ colonies are on islands. Name a few of the well established mainland based colonies. 11

12 The first Elephant Seals were seen on Año Nuevo Island; what year was this? The first pup was born on the island in They arrived on the mainland in 1967 and the first birth was in

13 What are the lengths of adult male and female elephant seals? Males: 14 to 16 feet Females: 9 to 12 feet 13

14 How long can males and females live? Males: 15 years - Females: 21+ years. 14

15 How much do adult male and female Northern Elephant Seals weigh? Males weigh between 3,000 and 5,000 pounds and Females weigh between 500 and 1400 pounds. Historical data reveals that some bulls weighed as much as 6,000 pounds but the present day mature bull weighs less. 15

16 Elephant Seals can sleep on the beach with very shallow breathing for minutes at a time. How is this adaptation advantageous for them? It conserves both water and energy. 16

17 Elephant Seals have layered structures in their nasal passages that act as condensation chambers, recycling moisture from their breath and conserving water. What are these structures called? Nasal turbinates 17

18 What adaptations allow Elephant Seals to see better in the dark ocean depths? Large eyes that adapt quickly to the dark. Lots of rods in the retina. A reflective layer behind the retina that causes the light to pass through the rods twice. 18

19 Sometimes, it appears that elephant seals on the beach have watery eyes. Why do they have these secretions? These oily secretions protect their eyes from salt and sand 19

20 How many teeth do elephant seals have? 30 – Only about an inch of the long canines protrude from the gums. Most pups have a full set of teeth within 34 days. It takes longer for the male’s teeth to erupt than female’s. 20

21 During the breeding season, adult males begin arriving in what month? Toward the end of November 21

22 Why do the males arrive before the females? To set up a hierarchy of the dominant bulls 22

23 How long are the males on the beach? Three months Many remain well into March 23

24 During the breeding season, how do the bulls sort out the hierarchy? By posturing, vocalization, and actual combat 24

25 By the time the females start arriving in mid- December, the males have already sorted out who gets prime positions on the beach to build their harems. Harems usually consist of how many females? 20 to 50 25

26 Female Elephant Seals usually give birth the first time at what age? 4 years is most common. The age at first birth ranges from 3 to 6 years, which means first conception is from 2 to 5 years of age. 26

27 Upon arriving on the beach, females have their pups within how many days? Usually within 5 days. 27

28 In what two ways do mothers and babies bond shortly after birth? Sound and Smell 28

29 After pups are born, they will usually begin nursing within the first few hours but it can take up to a day. Their mother’s milk contains an extremely high fat content. How does it compare to cows milk? Elephant seal milk averages about 55% fat compared to 4 – 6% fat for cows. 29

30 What percentage of weight does a female lose during birthing and mothering? 30 to 40% 30

31 At birth, what is the length and weight of an elephant seal pup? 3 to 4 feet long and 60 to 80 pounds 31

32 What is normal weaning weight for a pup? 300 pounds. The range is 250 to 330 pounds 32

33 Some pups, who have been successful at milk stealing weigh as much as 500 to 600 pounds. They are affectionately called what name? Superweaners 33

34 Elephant seal pups are quite thin when they are born and possess a soft black coat. How long does it take to lose this black coat? The coat is molted at 4-6 weeks of age. By the time they leave for the sea, they have grown a new fur called lanugo and it molts into a shiny gray pelage. 34

35 What fraction of pups survive the first year? About one- third. Less than 23% reach age 4. 35

36 The female nurses her pup for nearly a month. During the last days of nursing, what change does her body go through indicating she is ready for mating? Estrus 36

37 Elephant Seals are sexually dimorphic. What is sexual dimorphism? Where one gender is significantly different than the other. An adult male elephant seal is much larger than a female adult and has a proboscis and a chest shield. 37

38 Although male elephant seals are sexually mature at age 5 to 6, they aren’t serious contenders for breeding until what age? Age 9 when they reach physical maturity. Prime breeding age for them is 9 to

39 How long is the gestation period for an elephant seal? 11 Months – However, elephant seals delay implantation 3 to 4 months. 39

40 What is delayed implantation? Delayed implantation is a reproductive strategy in which the fertilized egg, undergoes a few cell divisions then halts development at the blastocyst stage. This delay allows the female to regain some of her depleted body mass and to molt. After these processes it attaches to the uterine lining for normal development. Other mammals who experience delayed implantation are rodents, bears, badgers, otters and kangaroos. 40

41 It has been speculated that most elephant seals return to beaches where they were born to mate. Researchers track them by attaching numbered, colored tags to the rear flippers of weaners. What color tag is used here? 41 Green

42 Elephant seals are remarkable divers. Their typical dives are between 1500 and 1900 feet. What is their maximum diving depth? The deepest recorded elephant seal dive is 5750 feet by a female (recent data). On average females dive deeper than males, possibly because of where they are feeding. The only mammals which dive deeper are the sperm whale and beaked whale; both of which can dive beyond 6000 feet. 42

43 How are elephant seals able to dive so deep? Before they dive, they exhale. Their empty lungs enable them to dive without swimming hard and without developing either nitrogen narcosis or the bends. 43

44 What physiological changes occur to elephant seals during these dives? Their heartbeats slow from beats per minute to about 20 and the flow of blood is diverted to the vital internal organs and brain, away from the extremities. These changes reduce oxygen use. 44 One elephant seal

45 During deep dives and while fasting on the beach, elephant seals can conserve energy by not breathing while their heart rate decreases. This period can last from 8 to 25 minutes. On the beach this non- breathing state is called what? It is a form of Sleep Apnea 45

46 What do male and female elephant seals eat? Males eat bottom dwelling prey such as skates, rays, ratfish, small sharks, octopus, hake, hagfish, rockfish and crabs. Females are thought to eat primarily squid and a variety of fish species (including lantern fish) according to where they forage, but will eat any of the above that they come across. Currently the dominant prey species have yet to be adequately defined

47 When do the Elephant Seals molt? The females and juveniles molt first, during the spring. Sub-adult males in the late spring and early summer. Adult males molt during the summer. 47

48 What is a catastrophic molt? Elephant seals return to the beach once a year after the birthing-mating season to molt. They replace an entire layer of epidermis and hair follicles in about one month. Humans grow and shed hair and skin continually, barely aware of the replacement process. Elephant seals must experience this catastrophic molt on land due to the frigid temperature of ocean and the need for blood at the epidermis. 48

49 What usually causes the circular scars found on elephant seals? Cookie Cutter Shark bites 49

50 What do Cookiecutter Sharks look like? The Cookiecutter Shark, also known as the cigar shark, is around 17–22 inches in length. It has a long, cylindrical body with a short, blunt snout, large eyes, and a large tail fin. Needle like teeth on top and large cutting teeth on the bottom. 50

51 What are the two main predators of the elephant seal? Great White Shark Orca or Killer Whale 51

52 In what ways do elephant seals keep cool on the beach? Sand Flipping Holding a flipper up in the air so that the warm blood can be cooled Taking a dip in the water 52

53 When elephant seals leave the beach, where do they go? They follow the continental shelf to the north. The males feed off the Aleutian Islands while the females tend to head farther out to the open ocean west of Vancouver. They travel as far west as the international date line. 53

54 What law protects Elephant Seals? Marine Mammal Protection Act (MMPA) of 1972 MMPA prohibits “the act of hunting, killing, capture, and/or harassment of any marine mammal”. 54

55 Thanks for learning and caring! 55 Jim and Ramona Voge created the first version of this as a personal study aid and a tool for all docents. Kathy Hurrle and Brandt Kehoe suggested new topics and did slide by slide analysis. The Friends of Elephant Seals Training Committee members worked with each revision and many of their suggestions are included here. Año adaptations made by State Park Interperter Mike Merritt and Año Docents Trevleyn Williams and Ed Lambing.

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