Suborder Cetacea

Question 1

Cetacea is Fully adapted to aquatic life.

Answer 1

• Feed at the middle or top of marine food web

* Ability to echolocate

Question 2

• First whales from Eocene (~50 MYA) of Tethys Sea

Answer 2

– Transitional semi-aquatic forms
– Lacked baleen, had teeth
– Large eyes—suggests they hunted fish

Question 3

Some later forms (Mysticeti) had both teeth and baleen

Answer 3

• Limited bulk filter feeding possible

Question 4

Middle Miocene mysticetes lost teeth

Answer 4

• Elongate rostrums to support more baleen

* Bulk filter feeding

Question 5

• Odontocetes (toothed whales) sister to

Answer 5

mysticetes

Question 6

Cetacea • Thick layer of subcutaneous blubber

• Testes remain abdominal

Answer 6

• Vertebrae with high neural spines
• Teats enclosed within slits next to
urogenital opening

Question 7

Cetacean Adaptations
• Must breathe air
– Able to alternate between 
– Rapid rates of 
– Twice the 
– 2–9 times 
– Blood bypasses 
• Blood flow to brain 
– Tolerate high levels

Answer 7

–periods of eupnea
and apnea
–  gas exchange in lungs
–  number of red blood cells
–as much myoglobin
–  certain muscles during diving
•  maintained
– of lactic acid

Question 8

Cetacean Adaptations
• Deep diving adaptations
– Many ribs lack connection to sternum
– Lungs dorsal to 
– Volume of non-vascular air spaces 
– Trachea short and 
– Bronchioles braced by

Answer 8

– lungs
collapse at depth
– diaphragm
–  is large
–  large in diameter
– cartilage rings

Question 9

Cetacean Adaptations
• Swimming adaptations
– Sub-dermal “springs” in tailstock
– Drag reduced on body surfaces
– Larger body mass increases speed

Answer 9

– store and
release elastic energy
– Compliant spongy layer in outer skin dampens
pressure and turbulence
– more favorable for thermoregulation

Question 10

Mysticeti Baleen whales

Answer 10

• Found in all oceans

* Populations decimated by whaling

Question 11

Mysticeti • Three distinct feeding modes

Answer 11

– Grazing near surface – right whales
– Lunge feeding – rorquals
– Bottom scraping – gray whale

Question 12

Family Balaenidae

are

Answer 12

• Right whales and bowhead whales

Question 13

Family Balaenidae

• Huge head and tongue

Answer 13

• Flippers short and rounded

* Dorsal fin absent

Question 14

Balaenidae – grazing

Answer 14

near surface

Question 15

Family Balaenopteridae

are

Answer 15

lung feeding Rorquals

Question 16

Family Balaenopteridae Baleen plates

Answer 16

short and broad

Question 17

Family Balaenopteridae have pleated or furrows throat

Answer 17

allow vast expansion of

throat during feeding

Question 18

Family Balaenopteridae have throat pouch contracted

Answer 18

water and food

pass through baleen plates

Question 19

Family Balaenopteridae Mandible braced

Answer 19

by fronto-mandibular stay apparatus

Question 20

Family Balaenopteridae may also use bubble nets

Answer 20

– Swim below school of prey
– Circle prey while emitting constant stream of
bubbles
– Swim rapidly up through middle of bubble net
– Engulf prey at surface

Question 21

Family Eschrichtiidae are

Answer 21

gray whale and are from • Parts of North Pacific

Question 22

Family Eschrichtiidae have Small head

Answer 22

short baleen plates

Question 23

Family Eschrichtiidae

exhibit third style of feeding

Answer 23

• Plow head through mud at bottom
• Scoop or suck up sediments
• Filter out marine organisms from bottom

Question 24

Family Odontoceti are

Answer 24

• Toothed whales, porpoises, and dolphins

* All oceans and seas, and some river systems

Question 25

Family Odontoceti teeth don’t occlude

Answer 25

• Homodont and monophyodont

Question 26

Family Odontoceti echolocate

Answer 26

some may stun prey acoustically

Question 27

Family Delphinidae are from

Answer 27

• All oceans and some large rivers

Question 28

Family Delphinidae have a

Answer 28

Fatty-deposit “melon” sits above and | behind snout

Question 29

Family Delphinidae • Rapid swimmers, regular leaps | • Highly gregarious

Answer 29

– Form schools – Highly vocal – Cooperative behaviors in some species – Intelligent

Question 30

Family Monodontidae are from

Answer 30

Arctic Oceans, Bering and Okhotsk seas, Hudson | Bay, and St. Lawrence River

Question 31

``` Family Monodontidae • Narwhal (Monodon monoceros) – • Beluga (Delpinapterus leucas) – ```

Answer 31

- long, straight, forward-directed tusk - white whale Both species: – Gregarious

Question 32

Family Phocoenidae are

Answer 32

porpoises

Question 33

Family Phocoenidae have short jaws and no beak

Answer 33

* Dorsal fin low or absent | * Form schools

Question 34

Family Physeteridae are

Answer 34

sperm whale

Question 35

Family Physeteridae • Huge blunt head

Answer 35

(one third total length)

Question 36

Family Physeteridae • Rostrum contains oil sacs—spermaceti organ and junk

Answer 36

• Oil important in former whaling industry

Question 37

``` Physeter of Family Physeteridae: – Social—groups of up to – Schools usually contain – Younger males form – Use powerful echolocation signals at – Feed on ```

Answer 37

``` – 1,000 individuals – one or more large males – “bachelor” schools – great depth – giant squid and fish ```

Question 38

Family Ziphiidae are

Answer 38

beaked whale | all oceans

Question 39

Family Ziphiidae have a single

Answer 39

lower tooth on each side on some | species

Question 40

Family Ziphiidae stomach

Answer 40

divided into 4–14 chambers

Question 41

Family Ziphiidae eat squid and deep-sea fish

Answer 41

• Teeth may be used primarily during intraspecific social interactions, and of little use during feeding

Question 42

River dolphins

Answer 42

* Family Platanistidae | * Family Iniidae

Question 43

Family Platanistidae are from

Answer 43

– Southern Asia

Question 44

Family Platanistidae | – Eyes are reduced

Answer 44

Echolocation important in murky waters | – Tend to swim on sides

Question 45

Family Iniidae – Amazon River dolphin (or boto) – La Plata River dolphin (franciscana) – Chinese river dolphin (baiji – extinct?)

Answer 45

* Inia geoffrenis * Pontoporia blainvillei * Lipotes vexillifer * Yangtze River