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Marine Mammals Order Cetacea Tamisha Michalewicz.

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Presentation on theme: "Marine Mammals Order Cetacea Tamisha Michalewicz."— Presentation transcript:

1 Marine Mammals Order Cetacea Tamisha Michalewicz

2 Order Cetacea Two suborders Two suborders –Mysticeti (Baleen Whales) –Odontoceti (Toothed Whales) One extinct suborder One extinct suborder –Archaeoceti (Ancient Whales) Live, Breed, Rest, and carry out all of their life functions in the water Live, Breed, Rest, and carry out all of their life functions in the water Archaeoceti

3 Cont. Inhabit all of the world’s oceans Inhabit all of the world’s oceans –As well as, some freshwater lakes, rivers, brackish waters of estuaries and coastal marshes

4 Mysticeti Most of the largest Cetaceans Most of the largest Cetaceans –i.e. Blue Whales (Balaenoptera musculus) which are the largest animal in history Exceeding 100 feet and weigh as much as 160 tons Exceeding 100 feet and weigh as much as 160 tons –Smallest is the pygmy right whale (Caperea marginata) Measure up to 23 feet Measure up to 23 feet –More examples: humpback whale (Megaptera novaeangliae), fin whale (Balaenoptera physalus), and southern right whale (Eubalaena australis)

5 Megaptera novaeangliae Humpback Whale – Megaptera novaeangliae cas.bellarmine.edu/tietjen/RootWeb/Chiroptera.jpg Balaenoptera physalus Fin Whale - Balaenoptera physalus

6 Odontoceti Largest and most diverse group Largest and most diverse group –i.e. the sperm whale is the largest Reaching about 60 feet Reaching about 60 feet –The largest living predator of warm- blooded animals is the killer whale –More examples: Dolphins and porpoises Sperm Whale – Physeteridae animals.nationalgeographic.com/staticfiles/NG...

7 Bottle Nose Dolphin – Tursiops trucatus Harbor Porpoise - Phocoena phocoena animals.nationalgeographic.com/staticfiles/NG

8 Taxonomic History Hippopotamids are closest living relatives Hippopotamids are closest living relatives –Followed by ruminants i.e. cows i.e. cows –Followed by Artiodactyls cas.bellarmine.edu/.../RootWeb/Artiodactyla.jpg

9 How do Cetaceans reduce drag for fast swimming? Fusiform body Fusiform body –Tapered at both ends Paddle-shaped front limbs Paddle-shaped front limbs No external digits or claws No external digits or claws Tail flattened laterally and bearing horizontal flukes at the tip Tail flattened laterally and bearing horizontal flukes at the tip Vestigial ear pinnae Vestigial ear pinnae Hairless body Hairless body Thick subcutaneous blubber layer filled with fat and oil Thick subcutaneous blubber layer filled with fat and oil

10 Cont. Addition of compressed vertebrae Addition of compressed vertebrae Shortening of the neck Shortening of the neck Lack of sweat glands Lack of sweat glands Internal reproductive organs Internal reproductive organs Three chambered stomach Three chambered stomach Telescoped skull bones Telescoped skull bones External nares on top of head External nares on top of head –Odontoceti have one blow hole –Mysticeti have two blow holes upload.wikimedia.org/.../300px-Cetacea.jpg

11 Coping with Cold Climates Small cetaceans Small cetaceans –Have high metabolic rates –Flippers and flukes have a countercurrent heat exchange system Heat from arterial blood warms venous blood as it returns to the heart Large cetaceans Large cetaceans –Small surface to volume ration Lose little heat to the surrounding environment Both are insulated by thick blubber layer Both are insulated by thick blubber layer

12 Physiological Adaptations for Deep Diving Rapid exchange in lungs Rapid exchange in lungs –Enhanced by double capillary layer in the intraalveolar septae –Humans use 4% of Oxygen inhaled, Cetacea use 12% –Twice the number of erythrocytes and myglobin molecules in their blood Allows for efficient capture and transport of oxygen Allows for efficient capture and transport of oxygen

13 Cont. Alter blood distribution Alter blood distribution –Rate of flow slows down (Undergo bradycardia) Heart rate slows by as much as 80 beats per minute Heart rate slows by as much as 80 beats per minute –Eliminated at non-critical organs via shunts i.e. digestive tract i.e. digestive tract –Reserved for critical tissues i.e. heart and brain i.e. heart and brain High tolerance to Carbon Dioxide and lactic acid build up in tissue High tolerance to Carbon Dioxide and lactic acid build up in tissue

14 Physiological Problems with Deep Diving Increased pressure with increased depth Increased pressure with increased depth At high pressure gases go into solution more quickly At high pressure gases go into solution more quickly Air breathing organisms have a problem with Nitrogen gas absorption into blood Air breathing organisms have a problem with Nitrogen gas absorption into blood –Causes decompression sickness i.e. Bends or Caisson’s Disease i.e. Bends or Caisson’s Disease

15 Physiological Solutions to Deep Diving Structural Adaptations Structural Adaptations –Lungs are small The total amount you take in = the total amount you let out The total amount you take in = the total amount you let out –Dead air spaces are large i.e. trachea and nasal cavity i.e. trachea and nasal cavity –Trachea is large and supported by cartilaginous rings –Bronchioles are small but braced by muscles and cartilaginous rings down to alveoli –Ribs are free from sternum Sperm Whale – Physeteridae

16 Cont. Mechanism Mechanism –Total exhalation before diving –Diving pressure forces collapse of lungs Forces air into dead air spaces, including nasal passages Forces air into dead air spaces, including nasal passages –Dead air spaces devoid of vascular tissue –Nitrogen is six times more soluble in oils then in water Blubber is highly vascular and serves as Nitrogen reservoir Blubber is highly vascular and serves as Nitrogen reservoir Oil also present in nasal sinus and may absorb nitrogen there as well Oil also present in nasal sinus and may absorb nitrogen there as well gimp-savvy.comgimp-savvy.com.

17 Mating Usually have one mating season per year Usually have one mating season per year Gestation is about 10 to 17 months Gestation is about 10 to 17 months Females give birth to a single calf every one to six years Females give birth to a single calf every one to six years Calves are born tail first and must swim from the moment of birth Calves are born tail first and must swim from the moment of birth Mysticetes nurse for about six months Mysticetes nurse for about six months Odontocetes nurse for over two years Odontocetes nurse for over two years

18 Social behavior Highly sociable within their respective species; often forming pods Highly sociable within their respective species; often forming pods –Pods often collaborate in hunting, playing, traveling, and taking care of young –Usually remain in pods throughout their life –Pods are beneficial because hunting is easier in a group; also pods decrease predation

19 Communication Flukes or Flippers Flukes or Flippers –Slap the surface Breaching Breaching –Leaping from the waters surface –Helps them to attain an elevation of several yards Spy-hopping Spy-hopping –Raise head out of water to investigate objects or potential prey

20 Cont. Emit various sounds from their head’s Emit various sounds from their head’s –Sperm whales have simple clicks –Humpback whales have complex “songs” –These sounds and echolocation help them navigate, investigate their surroundings, and hunt

21 Echolocation in Mammals Four orders of mammals use echolocation Four orders of mammals use echolocation –Order Cetacea (Whales, Dolphins) –Order Soricomorphia (Shrews) –Order Carnivora (Pinnepeds) –Order Chiroptera (Bats)

22 northern short-tailed shrew-Blarina brevicauda clackhi.nclack.k12.or.us/.../cute%20sea%20lion cas.bellarmine.edu/tietjen/RootWeb/Chiroptera.jpg

23 Echolocation in Cetacean Important means of navigation Important means of navigation Very well developed in Odontocetes Very well developed in Odontocetes Very Rapid Very Rapid –Size, shape, and distance of the object can be determined Anatomy of nasal regions Anatomy of nasal regions –Ducts and diverticula –Nasal plugs –Air cycled back and forth All are used to siphon air to create different sounds All are used to siphon air to create different sounds Hearing the return echo Hearing the return echo –Mandible Small thin bone, that allows the animal to hear through the lower jaw in front Small thin bone, that allows the animal to hear through the lower jaw in front

24 Food Mysticetes Mysticetes –Filter feeders Use their baleen to strain plankton and other tiny organisms Use their baleen to strain plankton and other tiny organisms Odontocetes Odontocetes –Feed on fish, squid, and crustaceans Larger species eat aquatic birds and mammals (which include other cetaceans) Larger species eat aquatic birds and mammals (which include other cetaceans)

25 Prey debilitation by Odontoceti Spermaceti organ Spermaceti organ –“Shocks” prey so they can eat

26 Ecosystem Roles Vital roles as consumers Vital roles as consumers Host a range of internal parasites Host a range of internal parasites –Cestodes in their intestines (Tetrabothrium and Diplogonoporus) –Plerocercoids in their blubber (Phyllobothrium and Monorygma) –Trematodes in their stomachs, livers, intestines, and sinuses (Bolbosoma) Host a range of external parasites Host a range of external parasites –Cookie-cutter sharks (Isistius brasiliensis)

27 Cont. Cetaceans are mutualists with animals that feed on ectoparasites Cetaceans are mutualists with animals that feed on ectoparasites Birds have a commensal relationships with cetaceans Birds have a commensal relationships with cetaceans –Seagulls often follow schools of dolphins and consume small fish stirred up by the feeding cetaceans –Pilotfish (Naucrates ductor) sometimes accompany killer whales and eat scraps from their kills

28 Economical Importance for Humans Disadvantage Disadvantage –Impact commercial fisheries due to competition for fish Advantage Advantage –Hunted for meat, oil, and blubber in 19 th century Oil is used for lighting and heating Oil is used for lighting and heating –Important for entertainment and tourist industries Killer Whale – Orcinus orca

29 Human Impact on Cetaceans: Negative Commercial whaling in the 19 th and 20 th century decreased the populations of mysticeti Commercial whaling in the 19 th and 20 th century decreased the populations of mysticeti Many small odontocetes threatened by commercial fishing operations Many small odontocetes threatened by commercial fishing operations –Become entangled in nets and drown, or killed by explosives –They are killed on purpose because fishermen see them as competition Use of military sonar in the ocean and increase in ocean noise threatens cetaceans Use of military sonar in the ocean and increase in ocean noise threatens cetaceans All cetaceans face the threats of pollution and global climate change All cetaceans face the threats of pollution and global climate change

30 Human Impact on Cetaceans: Positive Commercial whaling was banned in 1986 Commercial whaling was banned in 1986 Captive breeding programs help critically endangered odontocetes Captive breeding programs help critically endangered odontocetes members.greenpeace.org/.../source/action_129.jpg

31 References De Maddalena, Alessandro. June Giants of the Deep. World and 1, 19:6 De Maddalena, Alessandro. June Giants of the Deep. World and 1, 19:6 Ellis, E. and A. Poor “Cetacea” (on-line), Animal Diversity Web. September 30, Ellis, E. and A. Poor “Cetacea” (on-line), Animal Diversity Web. September 30, Werth, Alexander J. June Mandibular and Dental Variation and the Evolution of Suction Feeding in Odontoceti. Journal of Mammalogy. 87:3, Werth, Alexander J. June Mandibular and Dental Variation and the Evolution of Suction Feeding in Odontoceti. Journal of Mammalogy. 87:3,


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