Mammalogy 4764 Fall 2009

Cetacea Changes over evolutionary time 10+ families, 79 species -- 30 million years 37 mya Early to middle Eocene, Ambulocetus about 50 mya. Pakistan. Basilosaurus 54 mya Listed Appendix I or II of CITES Savage and Long 1986

20 mya 40 mya

Cetacea Coyote

Changes in skull Common characters Cetacea “Migration” of bones Arrow is nostrils Vertebrae modifications Horse Fusiform body (cigar shaped) Nearly hairless

Basilosaurus Blubber insulation No sebaceous glands

Odontocete

Mysticete

Feldhamer

Savage and Long 1986

Cetacea Cetacea Reproductive characteristics Common characters Gestation: 9.5 to 17 months More phalanges in Mammary glands in slits next to urogenital opening front digit than typical.

Pilot Right Blue Human

1 Mammalogy 4764 Fall 2009

Cetacea Cetacea Odontocete Mysticete Differences in skull Mysticetes eating smallest prey because are filter feeders. Asymmetry Shape Note: length of skull 4 m! Teeth Echolocation Right moving along surface

Feldhamer Compare to which stirs up / scoops / suctions from bottom sediments

Cetacea Cetacea Gas exchange -- 2 layers of capillaries Locomotive adaptations Expiration of almost all air -- humans retain 20+% 2x as many erythrocytes per blood volume vs. terrestrial 2x to 9x concentration of myoglobin (stores oxygen) Force of muscles -- Heart rate declines to half on deep dives 30,000 kg out of water! Bypassing muscles Tolerance to high lactic acid levels 70 minute dives Insensitivity to CO2 levels Lungs collapse within 100 m of surface Swimming speed -- consistent with propelling out of water Many ribs not attached to sternum--allows collapse Lungs small relative to body size Flippers steer, Tail up/down for forward propulsion Volume of nonvascular air passages larger Trachea short and large diameter, internal support : 36 km / hr Bronchioles shorter, braced by muscles and rings : 55 km / hr Lungs have elastic fibers -- allows compression : 27 km / hr : 37 km / hr for 10 minutes – 150,000 kg

Cetacea: Suborder Mysticeti Cetacea: Balaenopteridae

4 families, 11 species in suborder

Right (Balaenidae) 2 genera, 6 recent species

2 genera, 3 recent species 11 m to 31 m long 18 m long, > 67,000 kg

Head 1/3 of length Up to 160,000 kg in blue whale ( musculus) Feed on plankton/schooling fish Feed on Examples: mysticetus Humpback whale Megaptera movaeangliae Southern Eubalaena australis Balaenoptera acutorostrata Northern right whale Eubalaena glacialis Blue whale Balaenoptera musculus

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Cetacea: Cetacea: Suborder Odontoceti

Gray whale Eschrichtius robustus 6 families, 67 species

1 recent species Toothed whales

15 m long, 31,500 kg Echolocation is “trademark”

10,000 to 22,000 km migration May acoustically “stun” prey North Pacific in summer Vaughn 22-14 South to Korea or California Sperm whales: Sharks and squid in stomach with no marks. Bottom feeders Whales with injured jaws could obtain prey.

Cetacea: Delphinidae Killer whale Orcinus orca Cetacea:

17 genera, 32 species 2 genera, 2 species

1.5 to 9.5 m long Monodon monoceros 1 tooth (1/0) 50 to 7,000 kg Beluga Delphinapterus leucas Shallow dives, surface often Beluga 6 m, 2000 kg Gregarious Move up rivers in summer

Cetacea: Physeteridae Cetacea: Ziphidae

2 genera, 3 species 6 genera, 19 species

Sperm whale Physeter catodon Some species have yet Pigmy ( spp.) to be seen alive

Physeter gregarious Stomach divided into Groups of 20-40 typical 4 to 14 Chambers.

Dive for over an hour

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