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UNCW BIO 358 - More Marine Mammals

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BIO 358 1st Edition Lecture 3Outline of Last Lecture II. Characteristics of PinnipedsIII. Pinniped BreedingIV. Human impacts on pinnipedsA. indirectB. direct V. Pinniped DistributionVI. 3 families of pinnipedsA. Family Otariidaei. Characteristicsii. Example speciesB. Family Phocidaei. Characteristicsii. Example speciesC. Family Odobenidae i. Example specie D. Fun words about scrotums… Outline of Current Lecture VII. Odobenidae – Walrus VIII.Mustelidae - OttersA. Sea OtterB. Marine OtterIX. Ursidae – Polar Bear X. Order Sirena A. ManateeB. DugongC. Steller’s Sea CowXI. Beginning of Cetaceans Current LectureWalrus (odobenus rosmarus) - largest pinniped except for the elephant sealThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- “tooth walker” - only extant species in order and family odobenidae - only extant species with tusks - both males and females have tusks- for fighting and for pulling out onto ice and for hanging on to ice- swim like phocids using their hind flippers for lift based thrust force and they have one side expanded and one side folded in = lift based thrust Otters – Mustelids - sea otter and marine otter – both are endangered - exploited in 1740’s for fur- .5 million sea otters killed in 150 years until 1911- 1911 = north pacific fur seal convention, protected fur seals AND otters- sea otter #’s rose after thisSea otter – Enhydra lutris - largest otter- never seen on land- lies on its back and holds air in its large lungs and fur which makes it VERY BUOYANT - can hold rocks and abalones on its chest and still float- use hind flippers to produce lift-based thrust forces for high speed swimming - link hind limbs and dorsal ventrally oscillate Marine Otter (Lontra feline) - more terrestrial than a sea otter- most recent anscestor = bear - “sea cat”- found off the coast argentina and chile- more terrestrial than the sea otter- poached for fur coats- less than 1,000 individuals aliveFamily Ursidae - Polar Bear – Ursus martimus - only marine ursid- most recently evolved bear - 5.1-1 million years old – not a long time - closely related to brown bears - more streamlined than other bears- uses drag based thrusto i.e. Putting an oar in a water, thrust is not generated during the entire stroke. o Least efficient swimming style.. not as adapted for marine life as other marine mammals - Eats large endotherms: seals- Directly exploited for fur - Listed as threatened may 2008- Dr. Ian sterling studies these guys – he noticed a decrease in body condition and reproductive output over time… they will most likely be endangered soon because of GLOBAL CLIMAT CHANGE….- THESE ANIMALS ARE DEPENDANT ON ICE!o They are not highly adapted to swimming long distances because of their morphologyOrder Sirena- manatees and dugongs: - Restricted to warm waters (15 celcius 60 farenhite) colder than this = system wide breakdown called cold stress = death- Almost exclusively herbivores, sometimes they eat animals living on grass- “hind gut digesters” = non ruminant herbivore- eat A LOT every day ~55-90kg- have special teeth that are replaced through horizontal replacement… teeth emerge and reach the front and then fall out… like a conveyor belt - slow moving and placid animals- meat keeps well… people like to eat them - low metabolism- 70% Of time spent on sea floor- most closely related to elephants (hyraxes) - Trichiridae family = manateeso Teat in axilla (arm pit)o Many killed by boat strikeso Boat strike scar patterns = identification o Some have become dependant on warm water outfalls of power plants = conservation issueo COLD SHOCK happens very easily - manatees found in NC from may to October, if they are found in September they are dead (from the cold) o Have hugeeee tail flukeso West Indian Manatee (Trichechus Manatus) Endangered Sensitive to cold stress and need warm water- Family dugong = dugongs o Dugong (Dugong dugon)  Endangered Found in the indo-pacific Better swimmer, cetacean like fluke More streamline Lift base thrust for entire locomotary cycle- Steler’s sea cow (Hyrodamalis gigas)o HUGE ANIMALo Found in the arctico No functional teeth o Feed on kelpo Discovered in 1741 and was hunted for foodo Extinct by 1768… 27 years between discovery and extinction  o Keratin teeth plates = crushing kelpCetaceans: Telescope skull: – Nasal bone on top of head = blow hole/narins – Extended premaxilla and maxilla Baleen: – Right whales are skim feeders – Premaxilla and maxilla with paleen plates – Caratinized ~350 plates per side – Hiar like fringes at ends of plates – They gulp in water, close their mouths and then push it backwards through the


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