Marine Mammals

1. Marine Mammals

2. Marine Mammals “... Hmmm...Bottlenosed Bruises, Blowhole Burns, flipper prints, This looks like the work of rowdy teens, Lou cancel the prom ... .” – Chief Wiggum What are marine mammals? Mammals that live and feed in the marine (aquatic) environment What are Mammals? Mammary glands – nurse young with milk Hair Diaphragm Are Cetaceans Mammals?

3. Class Mammalia Order Carnivora Polar bears, sea otters, seals, sea lions, walruses Order Sirenia “Sea Cows” Manatees, dugongs Order Cetacea Baleen whales, toothed whales (e.g. sperm whale, dolphin, beluga, porpoise)

4. Polar Bear, Polar Bear, What Do You Hear? Order: Carnivora Suborder: Fissipedia (cleft foot) Family: Ursidae (Polar bear) Better viewed as a water-adapted terrestrial mammal Sustained swimmers Hollow (transparent) hair fibers too buoyant for diving

5. Sea Otters! Order: Carnivora Suborder: Fissipedia (cleft foot) Family: Mustelidae (Sea otter) - Keystone predator in kelp ecosystems - Feed on urchins & abalone - Fur for thermoregulation – 150,000 hairs/cm2 - Near TNZ – rely upon “heat increment of feeding” - eat > 25% of body wt / day

6. Suborder Pinnipedia “feather-footed” – 3 families 34-36 species – (25% of marine mammals) Phocidae – (true seals)19 spp. Otariidae – (sea lions, fur seals) 14-16 spp. Odobenidae – (walrus) 1 sp.

7. Seal or Sea Lion??? e.g. Steller sea lion, California sea lion, Galapagos fur seal, Northern fur seal, e.g. Harp seal, Northern elephant seal, Hawaiian monk seal

8. Hawaiian Monk Seals 3 Monk seal species (Caribbean & Mediterranean) All critically endangered (H & M) or thought to be extinct (C) Most primitive phocids More sensitive to human intrusion than other seals Population numbers are low (<1,500) and are decreasing due to: - death from predation by sharks - lower pup survival as the result of human disturbances - ciguatera intoxication - entanglement in fishing nets and debris - “mobbing” behavior - genetic bottlenecking – reduction in allele frequency (genepool) due to low number of individuals - disease

9. Order Sirenia “Sea Cows” Tropical/subtropical in shallow water Less sophisticated social behaviors than cetaceans Less specialization for aquatic existence Family Dugongidae Dugong (1 sp) Family Trichechidae Manatee (3 spp) All endangered

10. Order Cetacea “All he does is lie there like an unemployed whale.” – Bart Simpson 2 Suborders: Mysticeti – baleen whales (12-14 species) blue, humpback, grey whales Odontoceti – toothed whales, dolphins, porpoises (≈ 75 species) Earliest recorded marine mammals Most diverse & adapted - marine existence

11. Order Cetacea “Oh, who thought a whale could be so heavy?! Cheese it! The feds!” – Moe Syzlak Mysticeti: Loss of teeth (except in embryonic stages) 2 blowholes; symmetric skull Development of large body size & heads Shortening on intertemporal region & neck Odontoceti: Presence of teeth in adults Telescoping of rostrum; Presence of melon Single blowhole; Skull & soft-tissue asymmetry

12. Order Cetacea “Oh, who thought a whale could be so heavy?! Cheese it! The feds!” – Moe Syzlak Mysticeti: Loss of teeth (except in embryonic stages) 2 blowholes; symmetric skull Development of large body size & heads Shortening on intertemporal region & neck Odontoceti: Presence of teeth in adults Telescoping of rostrum; Presence of melon Single blowhole; Skull & soft-tissue asymmetry

13. Order Cetacea Mysticete Odontocete

14. Mysticetes “They like you very much, but they are not the hell your whales.” – Mr. Spock Class: Mammalia Order: Cetacea Suborder: Mysticeti Family: Balaenidae (3 species – N. & S. right whales (Eubalaena), bowhead (Balaena) Family: Neobalaenidae (pygmy right whale) Family: Balaenopteridae (blue, fin, sei, Bryde’s, minke, humpback) Family: Eschrichtiidae (gray whale) 

15. Suborder Odontoceti “You know its the largest mammal on earth but as George says ‘they don't have to be’.” – Jerry Seinfeld Sperm whale (1) Pygmy/dwarf Sperm whales (2) Ganges River Dolphin (1) Beaked Whales (21) (1) Baiji River Dolphin (1) Bouto River Dolphin (1) Franciscana R. Dol. Narwhal/Beluga (2) Oceanic Dolphins (36) Porpoises (6)

16. Porpoise vs. Dolphin “Oooh. You're not sharks. You're dolphins. The clowns of the sea”. – Lenny Leonard

17. Marine Mammals Adaptations to an Aquatic Existence Insulated skin – blubber or dense fur Countercurrent heat exchange systems Eyes, nose, ears – terrestrial, FW, SW High Frequency sounds

18. Adaptations to an Aquatic Existence Insulated skin – blubber or dense fur Insulative value a function of thickness, lipid content, & peripheral blood flow Skin Skin Blubber Blubber Muscle Blubber Muscle Muscle Cetacean/Pinniped Manatee

19. Parallel intermingling vessels = vascular bundles (rete) Veins Artery 37°C 35°C 39°C 33°C 31°C 29°C 27°C 28°C 30°C 32°C 34°C 36°C 38°C Counter Current Heat Exchangers Heat is conserved before it is lost at the extremity

20. Adaptations to an Aquatic Existence Modified limbs – fore & hind limbs, tail Bowhead Whale Sea Lion Manatee

21. Flippers & Locomotion In cetaceans, pinnipeds, sirenians – forelimb proportions altered Pectoral fin is forearm & hand – elbow not external Also seen in marine reptiles, ichthyosaurs, mosasuars Pilot Whale Blue Whale Right Whale

22. Marine Mammals Relating Evolutionary Events