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Marine Mammals
1Picture: G. BearziWHO ARE THEY?
2Photo: webMarine mammalsLand-dwelling ancestorsWarm-bloodedBreathe airHair/furBear live youngMammary glands for milkThey all have 3 ear bones.
Cetacea (se-tay-she-ah)whales, dolphins, and porpoisesCarnivorapolar bears, otters, seals, sea lions, walrusesSirenia (sire-een-e-uh)manatees and dugongs
Three Categories ofMarine Mammals4Photo: webCETACEA: Toothed whales
5Photo: M. Bearzi 2000Bottlenose dolphinStriped dolphinCommon dolphin
6Images: M. DemmaRissos dolphinFocena comuneGlobicephalo...Killer whale
False killer whale
Rough-toothed dolphin
7Images: M. Demma
Rissos dolphinHarbor porpoisePilot whale
8Images: M. Demma
Sperm whale...
Cuviers beaked whale9Images: M. Demma
SPERM WHALE
Not much of a species barrier!11
CETACEA: Baleen whales
15Photo: web
Fin whaleRight whaleSei whaleHumpback whale16Images: M. Demma
CetaceaAdaptations for deep divingUse oxygen efficientlyAbsorb 90% of oxygen inhaled (lots of capillaries)Store large quantities of oxygen (lots of hemoglobin)Reduce oxygen required for noncritical organsDive 10 min (dolphin) to 2 hours (Sperm Whale)Muscles insensitive to buildup of carbon dioxideCollapsible lungsTemperature RegulationBlubber (also for buoyancy and energy storage)Counter-current blood flow warms blood as it returns tocore of bodyMuscles generate heatLow surface area to volumeratio - little surface in contactwith water to lose heat
20Oxygenblowhole (nostrils) on head easierEmpty and fill lungs quickly (2 seconds for a fin whale)Large lungsHigh gas exchange rate (absorb 90% of oxygen - humans absorb 20%)
21OxygenMany red blood cells, hemoglobin carries oxygenmyoglobin - carries additional oxygenShunt blood from non-vital organs (stomach, kidney) when diving to vital organs (brain, heart, muscles)Slow heartbeat rate when diving
22Propulsion Through the WaterStreamlinedInternalized body parts - ear, penis, mammary glands reduces frictionShorter appendages forelimbs for steeringLoss of hind limbsLoss of hair
23
Propulsion Through the Waterfluke (tail) for propulsionUp and down (unlike fish = side to side) surface areaAlso to identify individuals - like fingerprintflippers for steering and balance
25Sensing the EnvironmentGood eyesight but little to no lightecholocation - biological SONAR find and maybe to stun preyVery good hearing - sound travels faster in water than in airex: humpback songs for communication social, territorial
26Cetaceans sensory worldSOUND
Communicationwhistles
Echolocationclicks
27Photo: web
Song of a whaleDolphin whistles
Cetaceans sensory world28Photo: web
Types of WhalesToothed whales suborder OdontocetiBaleen whales suborder Mysticeti29Types of Whales Toothed WhalesHave teeth to catch prey, not chewEat mostly fish and squid - killer whales eat sealsDive deeperMost do not migrateEx:sperm, pilot, killer whales, dolphins, porpoisesEx: sperm whales dive > 3,500 feet for giant squid, up to 75 minutes
30Types of Whales Baleen WhalesNo teeth - 600 - 800 baleen plates to filter krill and other itemsex: blue whale eats 4 tons of krill per dayNot deep diversex: humpback - lung feeding (lunge forward, pleats open), flick feeding (flick tail), bubble feeding (blow bubble net and swim up)
31Types of Whales Baleen Whalespleats folds under mouthopen like accordion when feeding
32baleenventral groovestonguejaw33Image: from M. Jahoda book, modified FeedingOther whales
34Image: G. Bearzi
Types of Whales Baleen Whalesex: humpback - lunge feeding (lunge forward, pleats open), flick feeding (flick tail), bubble feeding (blow bubble net and swim up)
35Types of Whales Baleen Whalesex:blue, humpback, right, gray, finNorth to feed, south to breed - behavioral adaptationnorth - summer for krillsouth - winter to raise youngex: gray whales, 3 monthmigration, Arctic to Baja, CA,6,000 mi one way
36Order CarnivoraPinnipeds (large skin covered flippers)WalrusesSeals Sea lionsFur seals
CARNIVORA: Pinnipeds
Otariidae sea lions, fur seals, etc
Phocidaetrue seals
38Photos: M. Bearzi 2000Family Phocidea (Pho-ce-die)True or Earless SealsNo external earsFlippers covered in furHind flippers cannot be turned forward under the body for use in terrestrial motionMoves on land by wiggling like a catapillar
Family Otariidae (ota-rye-uh-dee)
Eared SealsSea Lions and Fur SealsVisible external earsFlippers are hairlessHind flippers can be placed under body for awkward locomotionLonger front flippers
Sea Lion vs. Seal
Figure 9.09b
CARNIVORA: PinnipedsOdobenidae (Odo-ben-i-de)walruses
48Photo: web
CARNIVORA: Ursidaepolar bears
49Photo: web
CARNIVORA: Mustelidaesea otters, weasels, minks, etc
50Photo: web
SIRENIA:
Trichechidaemanatees
Dugongidaedugongs, Stellars sea cows
51Photos: web
Order Sirenia
Includes Manatees and DugongsSea CowsClosely related to elephantsNamed after sirens from Greek mythology. (mermaids)SireniansMove by moving tail up and downWell-padded with blubberA few scattered hairs
Sirenians:onlyeat seagrasses and other aquatic vegetation extremely low metabolism zero tolerance for cold water.
Sirenians are restricted to warm shallow coastal waters, estuaries, and rivers, with healthy ecosystems that support large amounts of seagrass and/or other vegetation.
A byproduct of their diet is that Sirenians produce a large volume of gas, which is given off during the digestion of plant material and this makes them particularly buoyant, so much so that their bones are dense in order to compensate
Four living species placed in two families make up this orderCompare that to:~78 species of cetaceans ~235 species of primates SIRENIA:
Amazonian manatee
African manatee
West Indian manatee
Dugong
Thought that the species was likely extinct by 1768.Extinct Stellers Sea CowHydrodamaliswas hunted primarily as a source of food. Steller (1751) describes the meat as being easily prepared and similar to beef in taste and texture.
The blubber was useful for:cooking lamp oil.
The milk of harvested cows was consumed directly or made into butter.
The thick, tough hide was used for shoes, belts and to make skin-covered boats.Once known to occur in large herds and have healthy populations, the Amazonian manatee has suffered from extensive hunting by subsistence and commercial hunters
Other Threats:The deforestation of large areas of the forests surrounding this manatees river habitats has also caused soil erosion, degradation of food supplies and the reduction of vegetation in the waterwayWatercraft collisions account for approximately 25% of all manatee deaths
Meanwhile in Florida..
http://live.wsj.com/video/mellow-manatees-at-the-center-of-a-storm/001901E5-5BC5-4544-8D2B-C17A9D74119B.html#!001901E5-5BC5-4544-8D2B-C17A9D74119BAnderson (1995) has also noted that the intense hunting of sea otters on the Bering Sea islands may have contributed to the final extinction of Hydrodamalis. It is known that sea urchin populations can severely deplete sea grass and algae communities when otters are removed, and as this happened on the Bering Sea islands, the sea cows would have faced a new competitor for food. A similar course of events may have occurred 12,000-14,000 years earlier along the coast of Asia and North America as aboriginal peoples colonized the areas and began hunting otters and sea cows (Anderson, 1995).