Marine Reptiles, Birds, and Mammals

1. Marine Reptiles, Birds, and Mammals Chapter 9B

2. 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

3. 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

4. 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

5. 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/min12bpm

6. Swimming and Diving • Sirenians & Cetaceans • Move tail/fluke up and down • Blue and Killer Whales: 50kph31mph • Common dolphins: 64kph40mph (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

9. 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

10. 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

11. 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

12. 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=Lk3ZxmptZy8

13. 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=WabT1L-nN-E

14. Behavior • Dolphins and humans • Stranding/beaching • Refuse to move/can’t be moved • Internal organs collapse • Pilot and sperm whales • Submarine sonar

15. 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!

17. Migration • It’s difficult for scientists to fully understand cetacean migration • How do they navigate? • Scientists use.. • Small radio transmitters • Satellite

18. 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

19. 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

20. 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

21. 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