Marine Reptiles, Birds, and Mammals Chapter 9B. Biology of Marine Mammals Little is actually known...
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Transcript of Marine Reptiles, Birds, and Mammals Chapter 9B. Biology of Marine Mammals Little is actually known...
![Page 1: Marine Reptiles, Birds, and Mammals Chapter 9B. Biology of Marine Mammals Little is actually known about many marine mammals –Difficult or impossible.](https://reader036.fdocuments.in/reader036/viewer/2022081421/56649ebe5503460f94bc7e6e/html5/thumbnails/1.jpg)
Marine Reptiles, Birds, and Mammals
Marine Reptiles, Birds, and Mammals
Chapter 9BChapter 9B
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Biology of Marine Mammals• Little is actually known about many
marine mammals– Difficult or impossible to keep in captivity– Difficult to observe for long periods of time at
sea• Some whales and dolphins are rarely
seen• What little we know comes from captive
or stranded individuals
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Swimming and Diving
• Streamlined-hydrodynamic • Pre-Dive: hold their breath for 15-30s,
then rapidly exhale and take a new breath
• Up to 90% of the oxygen contained in the lungs is exchanged during each breath – Only 20% in humans
• Better at absorbing and storing oxygen• More blood than non-diving mammals
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Swimming and Diving
• Higher concentration of red blood cells, and thus more hemoglobin
• Muscles are extra in myoglobin• Heart rate slows while diving• Blood flow to non-essential parts of
the body is reduced• Lungs collapse-prevent the bends• Flexible rib cage which gets pushed
in
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Swimming and Diving
• Seals, Sea Lions, & Other Pinnipeds– Swim by moving their flippers
• Sea Lions: 35kph 22mph
– Pinnipeds will jump out of the water to take a breath (when swimming fast)
– Prolonged dives to great depths• Sea Otters: 4-5min, 55m• Pinnipeds: up to 30min, 150-250m
– Slow heart rate• Northern Elephant Seal: 85
beats/min12bpm
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Swimming and DivingSwimming and Diving
• Sirenians & Cetaceans– Move tail/fluke up and down
• Blue and Killer Whales: 50kph31mph• Common dolphins: 64kph40mph (Cause
they’re cool)
– Blowhole• Spout/blow- warm breath condensing,
combined with mucus and seawater – Used to identify the whale
– Blubber– Toothed whales= Master divers!
• Sperm Whale (Champ): 2,250m
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Echolocation
• Excellent vision… But echolocation is way cooler– Based on hearing
• Finding prey, orient to surroundings• Toothed whales, dolphins and porpoises,
and some pinnipeds (maybe baleen) • Emit sound waves, listen for the echoes • Echoes are analyzed by the brain• Time it takes=how far away object is
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Echolocation
• High frequency clicks-– High penetrating power– Can travel long distances– Used to obtain info about the
surroundings
• Low frequency clicks- – Stunning prey?– Discriminate detail– Locate nearby prey
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Echolocation
• Air is forced through air passages-closed blowhole
• Frequency-contracting/relaxing muscles along air passages/sacs
• Melon-focuses/directs outgoing sound waves
• Spermaceti organ-larger, buoyancy? Absorb nitrogen?
• http://www.youtube.com/watch?v=EFu_ef9XypY
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Behavior
• Highly social – Pinnipeds live in colonies for breeding– Cetaceans live in organized pods
• Sounds/vocalizations– Different from sounds used for
echolocation– Social and sexual signaling– Grunts, barks, squeaks, chirps, “moos”– Sounds moods– Whistles signature
• Dialects• http://www.youtube.com/watch?v=Lk3ZxmptZy
8
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Behavior
• Sounds/Vocalizations– Maintain distance between individuals– Breeding, feeding, alarms, birth– Humpback whale songs- serenading
• Communicate with body language• Play behavior- fun fun fun!• Breaching- get rid of parasite, warning,
viewing surroundings• No one left behind• Teamwork!• http://www.youtube.com/watch?v=WabT1
L-nN-E
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Behavior
• Dolphins and humans• Stranding/beaching
– Refuse to move/can’t be moved– Internal organs collapse– Pilot and sperm whales– Submarine sonar
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Migration
• Pinnipeds and cetaceans– Feeding grounds breeding grounds
• Most toothed whales don’t migrate• Baleen whales
– feed during summer – In the productive waters of the polar
regions– Diatoms and krill– Migrate to warmer waters to breed in
winter
• Gray whale- Longest migration!
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Migration
• It’s difficult for scientists to fully understand cetacean migration
• How do they navigate?• Scientists use..
– Small radio transmitters• Satellite
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Reproduction
• Pinnipeds– Breed on land/ice– Seals
• Male only breeds with one female• Males ‘rumble’, quiver necks, make bubble
shows
– Sea Lions, fur seals, elephant seals• Male breeds with many females• “Breeding territories”
– Harems (up to 50 females)– ‘Burned out’ – Bachelor groups
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Reproduction
• Pinnipeds– Give birth on shore– Close relationship with pup
• Must recognize pup’s call and smell• Pups can not swim at birth • Nursed for 4days-2months
– Female can become pregnant only after ovulation (occurs soon after birth of her pup)
– Gestation-less than a year– Delayed implantation
• Only visits breeding ground once a year
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Reproduction
• Cetaceans– Great whales- sexual maturity @ 5-
10yrs– Sexes are segregated within the pod
• Males perform courtship displays
– Gray Whales- third party help..– Gestation lasts for 11-12 months in
most • Relatively short• Sperm Whale: 16 months• Synchronized with migration to warm
waters
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Reproduction
• Cetaceans– Calves are born tail first
• Stay connected to placenta- no oxygen depravation
– Calf swims/helped to the surface– Fat-Rich milk rapid growth– Born without blubber
• Must gain weight before migrating with mom to polar feeding grounds
– Close relationship between mom and calf • Return to mommy in times of danger/stress