Marine Mammals Part 2

Circulatory Adaptations Counter-current heat exchange Heat flows from warmer blood to colder blood Areas likely to lose heat: – Mouth – Extremities – Eyes

Metabolic Adaptations Relatively high compared to terrestrial Brown Adipose Tissue (BAT) – Used strictly for heat when metabolized – Found mainly in pinnipeds

Behavioral Warm Up – Sit in sun – Lay on top of each other (thigmotaxis) Ex. Pinipeds Cool Down – Sleep (decrease metabolism) – Shade

Intelligence and Communications What is intelligence? How do you measure in Marine Mammals?

Size of Brain? EQ- Encephalization Quotient- measure of brain weight/ body weight Humans 5.07 Bottlenose dolphin 3.60 (various dolphins ranging from ) Ringed seal 1.37 Manatees.32 – Sperm whale: have larges brain (~7 kg or 17 lbs) – Human brain: ~3 lbs

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

Communication Transfer of information 3 case studies – Dolphin Signature whistles – Orca Whistle – Humpback Whale songs

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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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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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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Language “all language is a form of communication but not all communication is a form of language” “words”

Learning Studies Dolphins – Short term memory study: Auditory learning- excellent Visual learning - ~60% correct – Long term memory study: Both senses are good

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

Odontocetes Beaked whale

Mystecetes Baleen Whales

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

Walrus

Leopard Seal

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

Harbor Seals

Manatee and Dugongs

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”

Sea Otter

Polar Bear

Sea otters- Carnivore – No sharp cutting edge on teeth Polar Bears – Less specialized than other bears – Not developed grinding teeth

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

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

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

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

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

– 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

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