Marine Mammals
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Transcript of Marine Mammals
Marine Mammals
Kingdom Animalia
Phylum Chordata
Class Mammalia
General Characteristics
Endotherms: “warm-blooded” or able to maintain a constant temperature through their metabolism
Viviparous: embryo receives nutrients and oxygen through the placenta (exceptions: platypus and akidna)
Mammary glands: produce milk for newbornHair: at some point in their lives they have
hair/fur.Blubber: thick layer of fat to keep warm
Class Pinnipedia (Pinnipeds)
Seal, Sea Lions and WalrusesPredators: feed mostly on squid and fishBodies are streamlined and adapted for
swimmingPaddle-shaped flippersRelated to dogs and cats
Seals
Family Phocidae: True Seals Lack ear flaps (pinnae) Fore-flippers are short and have claw on
each of the fine digits Hind-flippers cannot be rotated forward Swim with powerful strokes of rear
flippers Use only fore-flippers on land
Harbor Seal
Adults to left
Juvenile below
Harp Seal
Harp Seal
Elephant Seal
Largest pinnipeds20 ft long 4 tons
Sea Lions and Fur Seals
Eared seals= have pinnaeLong, hairless or only partially haired fore-
flippers with splayed digitsLarge hind flippers; can rotate beneath the
bodySwim mostly with fore-flippersCan sit on land with head and neck
raised.
California Sea Lion
Sea Lion Diagram
Fur Seals
Stellar Sea Lion
Walruses
Distinct pair of protruding tusksFeeds mostly on bottom invertebrates,
particularly clamsStiff whiskers act as feelersTusks used in defense and anchor on to
ice
Walrus
Sea Otter
Order CarnivoraSmallest marine mammalsWeighs 60 to 80 lbsLacks a layer of blubberDense fur to keep warmNeed to eat 25-30% of weight per dayEat urchins, abalone, mussles, crabs
Manatees and Dugongs
Order SireniaRelatives of the elephantsAlso known as a sea cowHerbivoresPrefer warm water
Manatee
•15 feet and 3,000 lbs
•Grayish in color
•Tail is broad and rounded
•3 species
•Found in Florida, South America and West Africa
Distribution
Dugong
•10 feet and 600 lbs
•Tail resembles a whales
•One species
•Found in Australia
Order Cetacea
Order Cetacea
Three suborders:Archaeoceti- “ancient whales”; all extinct
Mysticeti- “mustached whales”
Odontoceti- “toothed whales”
1. Suborder Mysticeti (Baleen Whales)
Filter feeders, eat plankton & small fishBaleen plates- made from protein, comb/
strain planktonLargest whales- 150 tons; heart the size
of a compact car; Blue whale: 103 ft.Two blowholes, create a v-shape
Baleen Plates
a. Family Balaenidae (Right Whales)
Slowly swim at the surfaceMany (more than 200) relatively short
baleen platesNo throat pleats4 species; N & S Right Whales, Pygmy, &
Bowhead
Northern Right Whale
Southern Right Whale
Pygmy Right Whale
Bowhead Whale
b. Family Balaenopteridea (Rorguals)
Take in huge gulps of waterMany (more than 200) relatively short
baleen platesMany (32-100) long gular grooves: throat
pleats6 species; Blue, Fin, Sei, Bryde’s, Minke,
Humpback
Fin Whale
Sei Whale
Bryde’s Whale
Minke Whale
Humpback Whale
c. Eschirichtiidae (Gray Whales)Feed by scraping the bottom floorFewer baleen plates (130-180)No dorsal fin; 6-12 prominent dorsal
knucklesOne species; California Gray Whale
Gray Whale
B. Suborder Odontoceti (Toothed Whales)Peg-like teeth
Active hunters
More social than baleen whales
1. Family Physseteridae (Sperm Whales)
Spermaceti- white waxy material in head mistaken for sperm
Largest of the toothed whale; largest carnivore
No gular groovesDorsal fin or humpPrey on squid: Whale from Moby Dick
Sperm Whale
Size Comparison of Sperm Whale
2. Family Monodontidae (Narwhal and Beluga)Melon- fatty tissue used in echolocation8-11 irregularly shaped teethNo dorsal fin (to deal w/ sea ice or to
preserve body heat)Narwhal- long tusk thought to be used as
a show of dominance in males
Beluga Whale
Narwhal
3. Family Ziphiidae (Beaked Whales)Reversed sexual dimorphism- females are
larger than malesBeak is similar to dolphins1-2 pairs of teeth in lower jawFeed on bottom of ocean floorLongest dive-85 minutes
Beaked Whales
4. Family Delphinidae (Dolphins)
Largest familyMost intelligentConical teethCurved dorsal finIncludes Bottlenose, Orcas, Pacific White
sided dolphins and more.
Bottlenose Dolphin
Orca (Killer Whale)
5. Family Phocoenidae (porpoises)
Smaller than dolphinsRounded heads, smaller beak or absentFlattened spade shaped teethTriangular dorsal fin
Porpoise
River Dolphins (4 Families)
Most EndangeredTriangular, small dorsal finPoor eyesightLong beakMostly freshwater, one lives in brackish
estuariesFound in the Ganges in India, Amazon in
S.A., Yangtzee in China, and the La Plata River Dolphin in S.A.
Amazon River Dolphin
River Dolphins
B. Skeletal System
1. Axial skeletona. skull- reflects lifestyle of cetacean
1. Thorax- Sternum- collapsible2. Ribs- in odontocetes they have two heads and one or more costal cartilage for collapsing rib cage
2. Appendicular skeletona. The development of flippers has been
accompanied by an increase in the number of phalanges
b. Vestigial hip bone
Skeletal System of a Sperm Whale
Vestigal Hip Bone
C. Soft Body Anatomy
1. Dorsal fin and Flukes- Dorsal fin highly vascularized with a
counter current blood flow system- Cetaceans are capable of opening and
closing arteries and veins- vasoconstriction to preserve heat.
2. Blubber
Varies in thickness (up to 2 feet thick in bowhead whales)
Smaller whales- couple of inches Large whales- up to a foot
3. Muscles
Rich in myoglobin- keep oxygen level high in muscles
D. Feeding
1. Baleen Whales
a. Open mouth wide, taking in large quantities of water, and then closing mouth- Rorquals
b. By swimming through the water, mouth open- Right Whales
c. By using suction created when the tongue is pressed against a plate to draw water and food into the mouth- Gray Whales
FOOD
Plankton, copepods, krill, small fish
Size and flexibility of bristles and density is related to food preference (ex. If the whale eats plankton, it has very fine and dense bristles)
2. Odontocetes- toothed whales
PredatorsFOOD- mostly fish and small animals,
some seals
D. Swimming and Diving
1. Swimming- streamlined shape, dorsal fins, evenly distributed blubber
2. Diving- Have more blood with more red blood cells-
higher concentration of oxygen Heart rate slows, blood flow to the extremities
is reduced- bradycardia Collapse their lungs and rib cage squeezing
the air in the lungs into the blood- to help resist high pressure
E. Echolocation (“sonar”)
Animal emits sound waves, which travel about 5X faster in water than in air, and listens for the echoes that are reflected back from surrounding objects
Clicks- high pitched soundsMelon- helps to pass clicks forwardSpermaceti organ- filled with a waxy substance;
buoyancy regulator or sound reflectorOdontocetes use their oil filled jaw bones to
receive sound and direct it to the inner ear.
F. Behavior
Most cetaceans spend their entire lives in highly organized pods
Vocalization-Different sounds are associated with various moods and
social signalingsHumpback songs- canaries of the sea, sing specific
songs (vocalization)Breaching- out of waterStranding- swim to shallow water, it is a mystery why.
Migration
Cold to warm waters for giving birthFeed in polar regions (krill)Follow same patterns
Birth and Care of Young
Internal testes and penisGestation- 9-18 monthsBorn tail first- calf swims immediately to the surface once
bornLaboring mother are tended by one or more adultsCetaceans nurse with a pair of teats concealed in slits
along the body wall in the femaleMilk- produced by mammary glandsLow birth rate- one calf every three yearsSexually mature at age 7 to 14 yearshttp://www.enchantedlearning.com/subjects/whales/
anatomy/Repro.shtml