Sea Lions & Seals
Total Page:16
File Type:pdf, Size:1020Kb
Sea Lions & Seals Jamie Barry, Maggie Haas, & Olivia Sanchez Pinnipedia Pinnipedia (“Seals”) All true seals and sea lions belong to the clade Pinnipedia. This clade is comprised of three families - Odobenidae (Walruses), Otariidae (Eared Seals), and Phocidae (True Seals). The term “seal” commonly refers to the order Pinnipedia, Phocidae (True Seals) Otariidae (Eared Seals) Odobenidae however both sea lions and Ringed seals, harbor Fur seals, sea lions Walruses seals, spotted seals, walruses are also classified as elephant seals, other Pinnipeds. true seals From the Latin pinna, feather or wing, and ped-, foot Who are the Pinnipeds? Photo by: http://www.pressherald.com/wp- There are currently 33 species of extant content/uploads/2016/03/811802_US_NEWS_ENV-SEALIONS_1_LA.jpg pinnipeds, each one exhibiting a few notable characteristics that distinguish them from other marine mammals. ● They are carnivorous aquatic placental mammals that heavily rely on the use of flipper-like front feet for swimming. ● The hands and feet of the pinniped are elongated and their digits are connected by webs of skin to act as flippers. ● Unlike most other marine species, the Pinnipeds are adapted to feed on fish, pinniped tail is very basic in function, as its mollusks, as well as other forms of marine steering is controlled by backward-facing hind mammal life. feet. Walruses ● These marine mammals are extremely sociable and Odobenus rosmarus can usually be found loudly bellowing and snorting at one another ● Only Native Americans are currently allowed to hunt walruses, as the species' survival was threatened by past overhunting ● Can live up to 40 years in the wild ● Can weigh up to 1.5 tons 6 ● Adult walruses are easily recognized by their prominent tusks, whiskers, and bulkiness ● This species is subdivided into three subspecies ○ The Atlantic walrus, the Pacific walrus, and the O. r. laptevi ● Has a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere 7 Photo by: https://en.wikipedia.org/wiki/Walrus Sea Otters ● Member of the Weasel Family Enhydra lutris ● Sea otters have the densest fur in the animal Sea otters are not classified as pinnipeds kingdom, ranging from 250,000 to a million hairs per due to their padded feet, their lack of square inch true flippers, and their thick, dark fur. ○ This is because they don’t have blubber to help keep them warm ● Sea otters are a keystone species ● Sea otters eat urchins, abalone, mussels, clams, crabs, snails and about 40 other marine species ● Native to the coasts of the northern and eastern North Pacific Ocean ● Hunted extensively for their fur between 1741 and 1911, and the world population fell to 1,000–2,000 individuals living in a fraction of their historic range¹ Photo by: https://www.thinglink.com/scene/694511142789185536 Sea Lions Photo by: http://a-z-animals.com/animals/sea-lion/ Quick Facts ● Life span: 20 to 30 years ● Gestation: 8 to 18 months, depending on species ● Number of young at birth: Usually one, rarely two ● Size: Females are 4 to 9 feet long; males are 6.5 to 11 feet ● Weight: Females are 110 to 600 pounds; males are 440 to 2,200 Photo by: http://justcuteanimals.com/post/7614 pounds 14 Steller Sea Lion Sea Lions in Eumatopias Jubatus -The most common species found in Alaska Alaska -Also known as “Winnaq” by the 9 ● Alutiiq people What are the different species? Photo by: https://caseagrant.ucsd.edu/project/explore-sandy-beach- ecosystems-of-southern-california/sandy-beach-plants-and- animals/marine California Sea Lion Zalophus Californianus -54 reported in Alaska from Photo by: http://www.marinemammalcenter.org/education/marine-mammal-information/pinnipeds/steller-sea-lion/ 1974-2004 8 ● They can primarily be found on the California Sea western coasts of Canada, the United States and Mexico 8 Lion ● Scientists have discovered 5 distinct variations of California Sea Lions: Southern Central California stock, Northern Gulf stock, Pacific Tropical stock, Pacific Temperate Stock and the Western Baja California stock ● Although there are some slight variations in habitat and location, California Sea Lions share the majority of their attributes, such as eating and mating behavior, with Steller Sea Lions Photo by: http://www.pittsburghzoo.org/animal.aspx?id=122 8 What do Sea ● Diets depend on region and time of year, Lions eat? but some species remain constant in a Sea Lion diet such as: Arrowtooth Flounder, Walleye Pollock, Atka Mackerel & Cephalopods ○ Referred to as opportunistic hunters ● Popular prey during certain times of year: Pacific cod, salmon and herring ● Occasionally eat true seals for “variety” ● They have the ability to eat prey in its entirety while under water ○ Special teeth ● Scientists study Sea Lion scat for answers 9 Photos by: https://mu-peter.blogspot.com/2014/01/cerebral-cephalopods-heady-head-feet.html http://www.elasmodiver.com/Pacific_Cod_Pictures.htm https://teacheratsea.wordpress.com/tag/mary-murrian-2/ Migration and ● Sea Lions do not migrate, but instead shift their central locations to have easier Breeding access to different types of prey throughout the year ● Rookeries are the optimal spot for summer breeding → then move to more secure haulouts (pieces of land) during the winter months ● Don’t tend to travel extraordinary distances → Pups can only swim approximately 75 miles, non-stop ○ Longest route ever recorded = 1,600 miles from Forrester Island to Cape 9 Photo by: https://en.wikipedia.org/wiki/Hauling-out Newenham ● Although initially born with dark fur, Life of a Sea Sea Lions lighten over time, most often resulting in a pale yellow Lion color (and some end up a reddish color) 9 ● Male Sea Lions are easier to spot because of their large bodies (heavy weight), muscular necks and broad foreheads ● Females grow at a rapid pace within the first 4 years, and then plateau, meanwhile the males can continue even after their 10th year9 9 Photo by: Maggie Haas The life of a Sea ● Sea Lions divide their time between land (rookeries) where they rest and Lion cont. nurse the pups, and water ● Pups learn to fast while the mothers hunt (1-2 day trips) ● Swimming and diving techniques come with age ● Mature Sea lions can dive more than 1,500 feet and stay underwater for at least 16 minutes ● They use their back flippers to change direction and the front flippers Photo by: http://ocean.si.edu/ocean-photos/seal-or-sea-lion to gain speed 9 ● Sea Lions settle in more than 300 haulouts, with preference Sea Lion Habitats towards secluded islands that can protect them from predators ○ Females tend to chose the same haulouts to give birth ● Habitats can range from the North Pacific Rim of Japan to the East of the Aleutian Islands towards the Bering Sea, and Photo by: http://animals.nationalgeographic.com/animals/mammals/steller-sea-lion/ South to the Channel Islands off of California 9 Seals Photo by: https://en.wikipedia.org/wiki/Harbor_seal Quick Facts Fully grown male elephant seal ● Life span: 25-30 years ● Gestation: 10 months ● Number of young at birth: One pup per year ● Size: Smallest species is 3-4 feet long (baikal seal), largest is 13-16 feet long (elephant seal) ● Weight: smallest is ringed seal (110- 115 lbs) and the largest is elephant Photo by :http://www.seals-world.com/wp-content/uploads/2014/01/Northern-elephant-seal_624.jpg seal (2,000 lbs for females, up to 8,500 lbs for males) 8,9 Seals Found in Harbor Seal Range Alaska ● The Pacific Harbor seal (Phoca vitulina) and the Northern Fur seal (Callorhinus ursinus) are Photo by: http://www.seattleaquarium.org/view.image?Id=2150 the two species of seal that Northern Fur Seal Range can be found off the coast of Southern Alaska. ● Ice Seals, which include Ringed seals, Harp seals, and Spotted seals, can be found in Arctic regions of Northern Alaska Photo by: https://www.defenders.org/sites/default/files/northern-fur-seal- range-map.jpg Ice Seals A Ribbon Seal ● Ringed Seals (Phoca hispida) are among the smallest of the pinnipeds and are known for living in ice lairs in large snowdrifts to hide from predators ○ They are the most common and widespread seal in the Arctic ● Ribbon Seals (Phoca fasciata) are closely related to Harbor Seals and are the rarest seal found in the Arctic. They are known for the 3 large bands of white coloration found on their bodies ● Spotted Seals (Phoca largha) are often confused with Harbor Seals due to their similar coloration and geographic range, however, they give birth to their pups on sea ice, while the Harbor Seals give birth on land ● Bearded Seals (Erignathus barbatus) are the largest species of seal found in Alaska and are vital to coastal Alaskan villages due to the fact that they provide needed meat, oil, and skins to the native 17 communities Photo by :https://alaskafisheries.noaa. gov/sites/default/files/styles/large/public/ribbonseal_closeup_sm.jpg?itok=gr5p30S0 Each day, the Harbor seal consumes Diet about 5-6% of its body weight. ● Harbor seals and Fur seals will Additionally, these seals rely on food as congregate in intertidal zones and their primary water source, as they are harbors to find squid, crustaceans, unable to consume salt water 10 mollusks, and a variety of fish, including rockfish, herring, flounder, salmon, hake, and sand lance. 8 ● Rather than chewing their food, these seals will eat their food whole or tear it into larger chunks before swallowing it. ○ Strengthened back molars are responsible for crushing shells 10, 11 and crustaceans. Photo by: http://i.cbc.ca/1.2951993.1423595819!/fileImage/httpImage/image. jpg_gen/derivatives/4x3_620/seal-vs-octopus-1-slide-5.jpg Mating Photo by: http://www.zooborns.com/.a/6a010535647bf3970b015431e82c36970c-500wi Fur Seals ● Each year, male Fur seals stake out breeding grounds early in the mating season (Late Spring).