18. Order Cetacea Notes

CetaceansCetaceansKingdom: AnimaliaKingdom: Animalia

Phylum: ChordataPhylum: ChordataClass: MammaliaClass: Mammalia

Order: CetaceaOrder: CetaceaSuborder: MysticetiSuborder: MysticetiSuborder: OdontocetiSuborder: Odontoceti

Family: DelphinidaeFamily: DelphinidaeFamily: PhocoenidaeFamily: Phocoenidae

MammalsMammals

Evolved from reptiles 200 million years agoEvolved from reptiles 200 million years ago 4,500 species4,500 species Endothermic – warm-bloodedEndothermic – warm-blooded Brain size far larger in proportions than other Brain size far larger in proportions than other

organismsorganisms Have hair, mammary glandsHave hair, mammary glands

Evolution of WhalesEvolution of Whales Pakicetids are Pakicetids are

reasoned to be the reasoned to be the earliest ancestorsearliest ancestors

Lived on landLived on land Closest living animals Closest living animals

to whales are cows, to whales are cows, hippos, and giraffeshippos, and giraffes

Evolved into Evolved into archaeocetesarchaeocetes

More eel like form More eel like form that developed into that developed into modern whalesmodern whales

Ancient Whale AncestorsAncient Whale Ancestors

CetaceansCetaceans

Whales, dolphins, Whales, dolphins, and porpoisesand porpoises

All are completely All are completely adapted for life in adapted for life in waterwater

Bodies designed Bodies designed for streamline for streamline swimmingswimming

Breathe airBreathe air

General Exterior Body General Exterior Body StructureStructure

Pair of front flippers w/ similar bone structure Pair of front flippers w/ similar bone structure to our handsto our hands

Caudal fin end in a pair of fin-like horizontal Caudal fin end in a pair of fin-like horizontal flukesflukes

Blowhole – nostrils found on top of the bodyBlowhole – nostrils found on top of the body Some species missing dorsal finSome species missing dorsal fin

Flipper vs. Hand Flipper vs. Hand StructureStructure

General Interior Body General Interior Body StructureStructure

Small, useless pelvic bones are the rear Small, useless pelvic bones are the rear pair of limbs that never developedpair of limbs that never developed

Blubber – fatty layer that provides Blubber – fatty layer that provides insulation and buoyancyinsulation and buoyancy

MelonMelon

Special organ Special organ located between located between the blowhole and the blowhole and rostrum of toothed rostrum of toothed whaleswhales

Oil filled sac that Oil filled sac that serves as an serves as an acoustical lensacoustical lens

Spermaceti OrganSpermaceti Organ

Massive melon Massive melon found in sperm found in sperm whaleswhales

Filled with waxy Filled with waxy oil called oil called spermacetispermaceti

Used for lanterns Used for lanterns and candlesand candles

SwimmingSwimming

Cetaceans swim by Cetaceans swim by beating their beating their flukes up and down flukes up and down while maneuvering while maneuvering with their fins.with their fins.

BreathingBreathing

Can exhale and inhale at incredible rateCan exhale and inhale at incredible rate Blowhole allows for breaths while swimmingBlowhole allows for breaths while swimming Spout or blow – combination of warm breath, Spout or blow – combination of warm breath,

mucus, and seawater that differs whale to whalemucus, and seawater that differs whale to whale

Diving AdaptationsDiving Adaptations

Cetaceans hold Cetaceans hold breath for 15-30 breath for 15-30 seconds, then seconds, then quickly take a quickly take a breath to maximize breath to maximize oxygen consumptionoxygen consumption

Blood has higher Blood has higher concentration of red concentration of red blood cells which blood cells which can hold more can hold more hemoglobinhemoglobin

Reduce heart rate Reduce heart rate when divingwhen diving

Divert blood to Divert blood to vital organsvital organs

Collapsible lungs Collapsible lungs prevent the prevent the nitrogen from nitrogen from dissolving in blood dissolving in blood and thus getting and thus getting the bendsthe bends

EcholocationEcholocation

Nature’s version of sonarNature’s version of sonar Animals release sound waves which create Animals release sound waves which create

echoes which are analyzed by brainechoes which are analyzed by brain Created by the passage of air inside cetaceansCreated by the passage of air inside cetaceans Melon focuses the sound wavesMelon focuses the sound waves

VocalizationsVocalizations Play an important Play an important

role in role in communicationcommunication

Unique sounds for Unique sounds for each specieseach species

Used for all forms Used for all forms of communicationof communication

Humpback whale Humpback whale songs are used for songs are used for attracting matesattracting mates

Whale Songs

Baleen Whales - Baleen Whales - MysticetiMysticeti

““toothless” whalestoothless” whales Baleen – rows of Baleen – rows of

flexible, fibrous flexible, fibrous plates that hang from plates that hang from the upper jawthe upper jaw

Made of the same Made of the same material as hair and material as hair and nailsnails

Covered with bristlesCovered with bristles Filter water through Filter water through

and lick what has and lick what has been left behindbeen left behind

Baleen StructureBaleen Structure

RorqualsRorquals

Lower part of the Lower part of the throat expands throat expands when filtering foodwhen filtering food

Includes Includes humpback and humpback and blue whaleblue whale

Other Baleen Feeding Other Baleen Feeding MethodsMethods

Some whales skim Some whales skim the surfacethe surface

These ones have These ones have the largest plates the largest plates with the finest with the finest bristlesbristles

Others are bottom Others are bottom feeders who stir up feeders who stir up the bottom and the bottom and then filterthen filter

Toothed WhalesToothed Whales Teeth adapted for a Teeth adapted for a

diet of fish, squid, and diet of fish, squid, and other preyother prey

Use teeth to catch and Use teeth to catch and hold not to chew, hold not to chew, rather it is swallowed rather it is swallowed wholewhole

Ambergris – remnants Ambergris – remnants of indigestible food of indigestible food and debris that and debris that accumulates as sticky accumulates as sticky globs, used for globs, used for perfumeperfume

Dolphins & PorpoisesDolphins & Porpoises

Considered whalesConsidered whales Technically Technically

porpoises only porpoises only consist of a small consist of a small group of blunt-group of blunt-nosed whalesnosed whales

Dolphin & PorpoisesDolphin & Porpoises

Most of the small Most of the small whales called whales called dolphinsdolphins

Dolphins typically Dolphins typically have a distinctive have a distinctive snout called a beaksnout called a beak

Travel in large Travel in large groups called podsgroups called pods

Family DelphinidaeFamily Delphinidae

DolphinsDolphins BeakBeak Cone-shaped teethCone-shaped teeth Curved/hooked Curved/hooked

dorsal findorsal fin Included Killer Included Killer

WhaleWhale 32 species32 species

Family PhocoenidaeFamily Phocoenidae PorpoisesPorpoises Smaller than dolphinsSmaller than dolphins Small triangular Small triangular

dorsal finsdorsal fins No beakNo beak Small spade shaped Small spade shaped

teethteeth Travel in smaller Travel in smaller

groupsgroups 6 species6 species

Porpoise vs. DolphinPorpoise vs. Dolphin