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Published byLindsay Stokes Modified over 8 years ago
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Marine Mammals Part 2
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Circulatory Adaptations Counter-current heat exchange Heat flows from warmer blood to colder blood Areas likely to lose heat: – Mouth – Extremities – Eyes
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Metabolic Adaptations Relatively high compared to terrestrial Brown Adipose Tissue (BAT) – Used strictly for heat when metabolized – Found mainly in pinnipeds
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Behavioral Warm Up – Sit in sun – Lay on top of each other (thigmotaxis) Ex. Pinipeds Cool Down – Sleep (decrease metabolism) – Shade
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Intelligence and Communications What is intelligence? How do you measure in Marine Mammals?
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Size of Brain? EQ- Encephalization Quotient- measure of brain weight/ body weight Humans 5.07 Bottlenose dolphin 3.60 (various dolphins ranging from 2.43-4.45) Ringed seal 1.37 Manatees.32 – Sperm whale: have larges brain (~7 kg or 17 lbs) – Human brain: ~3 lbs
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Cerebellum/ Cortex Cerebellum- larger part of the brain, “thinking/memory” Cortex-smaller part of the brain, “motor skills” Thought: The larger the curves/surface area the smarter you are
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Communication Transfer of information 3 case studies – Dolphin Signature whistles – Orca Whistle – Humpback Whale songs
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Dolphin signature Whistles All bottle nose dolphins have them Short in duration (1-2 sec) Unique to each individual (like fingerprints) – Males have whistle similar to mother – Female have whistle different than mother Why? – Form at about 6 mo – Females stay with mother longer – Female whistle different to tell difference between mother and daughter
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http://www.dolphinear.com/sounds/d3.wav http://cetus.ucsd.edu/voicesinthesea_org/vid eos/videoBottlenoseAcous.html http://cetus.ucsd.edu/voicesinthesea_org/vid eos/videoBottlenoseAcous.html
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Orca Whistle Fairly short Complex dialect – Pod specific Each pod may have many They stay in pods whole life Matriarchal society – Oldest female is the highest up
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http://www.youtube.com/watch?v=ZwJ8gfng P80 http://www.youtube.com/watch?v=ZwJ8gfng P80 http://cetus.ucsd.edu/voicesinthesea_org/vid eos/videoOrcaAcous.html http://cetus.ucsd.edu/voicesinthesea_org/vid eos/videoOrcaAcous.html
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Humpback Whale songs Repetitive species specific vocalization Longer (8-22 min) Only males sing – Primarily to find mates Number of “themes” Sing for up to 22 hours Songs evolve/change every year
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http://www.youtube.com/watch?v=xo2bVbDti X8 http://www.youtube.com/watch?v=xo2bVbDti X8 http://www.dolphinear.com/sounds/hsong1.w av http://www.dolphinear.com/sounds/hsong1.w av http://cetus.ucsd.edu/voicesinthesea_org/vid eos/videoHumpbackAcous.html http://cetus.ucsd.edu/voicesinthesea_org/vid eos/videoHumpbackAcous.html
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Language “all language is a form of communication but not all communication is a form of language” “words”
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Learning Studies Dolphins – Short term memory study: Auditory learning- excellent Visual learning - ~60% correct – Long term memory study: Both senses are good
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Feeding styles Skimmers- large Baleen, swim slowly – Filter as swim – Ex. Baleen Whales Gulpers-large gulps, faster swimmer – Throat grooves – Open mouth almost 90 degrees – Push water out with tongue – Ex. Rogue Whales
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Odontocetes Beaked whale
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Mystecetes Baleen Whales
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Feeding Behaviors Feeding structures – Teeth Odontocetes – All grabbing teeth – Beaked whale: 1 pair of teeth, males get 2 nd as tusk – Killer whale- multiple teeth Mystecetes – Baleen: » made of keratin » Tapers from use and age » Caused hunting for Baleen
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Walrus
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Leopard Seal
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Pinniped Teeth- Otariids Walrus – Flattened “post canines” – Mostly suction feeding – Long canine teeth Used for aggressive interaction, pull up on ice, break ice, sense bottom Crabeater seal or Leopard Seal – Eats krill – Interlocking teeth – filter out water
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Harbor Seals
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Manatee and Dugongs
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Pinniped Teeth- Phocids Harbor seals – Unspecialized post canines used to grab Manatees and Dugongs- Herbivores – All chewing teeth – All molars (except in males) – Hard gums – Move lips to feed – Get warn down- continuously replaced “Conveyor belt”
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Sea Otter
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Polar Bear
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Sea otters- Carnivore – No sharp cutting edge on teeth Polar Bears – Less specialized than other bears – Not developed grinding teeth
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Digestive System Most swallow food whole Have large esophagus Just one intestine, not separate large and small Manatee does not have chambered stomach Cetaceans have multiple chambered stomachs – Fin whale-7 chambers – Bottle Nose dolphin- 3 chambers
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Bottle-nosed dolphins 3 chambers – Forestomach Food storage, muscular grinding No chemical break down only mechanical – Fundic stomach Many enzymes that break down foods Similar to ours – Pyloric stomach Similar to fundic stomach but less specialized
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Diet Categories Zooplankton – Differences between N. and S. hemisphere – Ex: seals Piscivore- eats fish and cephalopod – #1 group- most species in this group – Feeding Patterns Individually or groups – Ex. Squid
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Diet Categories Herbivores – Only sirenians – Eat wide variety of species Overhang vegetation, algae, sea grasses Benthic Invertebrates – Ex Sea Otters Dive ~2 min < 100 ft Lay on backs on surface Pack prey in excessive skin to take to surface (pouch) Use tools to break open Spend time grooming between foraging Hostage behavior – Males hold pups hostage for food
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Diet Categories Marine Mammals and Birds – Ex. Killer whales, Polar bears, Leopard seals – Move south in winter for warmer water – Killer whales 21 ft orca has 14 seals and 13 porpoises in stomach Different pods have different specializations Good at catching food – Tip ice so seals slide off
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– Polar bears Eat primarily ringed seals – Go after pups in the den – Also eat walrus, beluga whales, narwhalls – Southern populations eat eggs, birds and berries Eat just blubber and skin (peal it off) Stomach capacity of ~150 lbs Intimidating predator – Leopard Seals Populations have different specializations of prey Significant predator of seal populations and penguins – Picky towards food – Shake penguin inside out to get skin/feathers off Pursuit people
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Ecological Roles Energetic (energy intake and output) Community Composition – Top down impact Predator has influence on everything in lower tropic levels – Ex Walrus: Eat 6% body weight in bivalves a day (~12,000 clams a day) – Keystone predator Different communities depending on presence or absences of organism – Ex. Sea Otter, Urchins, Kelp
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