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Order Cetacea - whales, dolphins, porpoises

Order Cetacea - whales, dolphins, porpoises. Phylum Chordata; Class Mammalia. Cetaceans are grouped on the basis of their mouths:. a. Mysticeti –whales with baleen strainers for plankton; both nostrils have a blow hole.

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Order Cetacea - whales, dolphins, porpoises

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  1. Order Cetacea - whales, dolphins, porpoises Phylum Chordata; Class Mammalia Cetaceans are grouped on the basis of their mouths: a. Mysticeti–whales with baleen strainers for plankton; both nostrils have a blow hole b. Odontoceti–whales, dolphins and porpoises with teeth; carnivores; 2 nostrils but only 1 blow hole; smaller in size

  2. Marine Mammal Characteristics: 1. hair (at birth) 2. nurse young 3. breathe air 4. warm blooded 5. placenta (live births) 6. horizontal tail (ALL marine cetaceans)

  3. NOAA The Blue whale is the largest animal - 100 ft. long, 150 tons. The Narwhal has a tusk that is an 8 ft. left tooth, found only in males. Beluga whales are pure white as adults. These arctic whales called “sea canaries” because they vocalize so much. NOAA

  4. Dolphins are the most social and intelligent whale. - body temperature of 97.7 o F - 7 minutes between breaths - 25 miles/hr. swimming speed - River dolphins of South America cannot swim in a straight line Whales (and all marine mammals) are protected by the Marine Mammals Protection Act of 1972. It was passed in response to purse-seine killing of dolphins in huge 4,000 ft. long nets.

  5. However, many are still being hunted to extinction under the guise of scientific research or are by-catch of the tuna fishery. There are over 1 million reported deaths per year. Tuna caught on lines is “certified” as dolphin safe by company employees. International Whaling Commission (I.W.C.) is a whaler’s organization that sets quotes based on catch size. They are not a regulatory agency and compliance is voluntary.

  6. Cetacean adaptations to marine life: Swimming: result of powerful tail flukes. Fluke markings are used like fingerprints for individual whales identification. Along with dive patterns and other markings. Sei whales are fastest at 40 m.p.h. Digestion: multi-compartmentalized stomachs “chew” food, (even toothed whales don’t chew). Teeth are conical and unspecialized. Some baleen whales feed by swimming through pockets of plankton or using “bubble nets” to corral their food. Their stomachs can hold 2 tons of krill at one time. Toothed whales hunt in packs and seek out individual fish, penguins, seals, sharks or other whales.

  7. Circulation: High blood volume holds maximum oxygen and glucose levels. Some large whales have veins so large that a trout could swim through them. Blood can be shunted to brain, heart, lungs and muscles and away from stomach and kidneys to protect vital organs. NOAA A 4-chambered heart can transfer arteriole heat to the veins as blood flows toward the tail - called counter-current heat exchange.

  8. NOAA Blubber insulates against cold. Overheating is solved by sending blood to surface tissues (flukes and fins) and by-passing the countercurrent vessels. Whales in captivity exercise less and often lose the ability to cool off by straightening the fins.

  9. Senses: Vision is poor in most species. Vocalizations and echo-location compensate. Whales have no vocal chords but make songs, clicks and whines by vibrations in the blow hole. They may communicate to indicate territories, attract mates or act as homing devices for the young. Families of whales have their own dialect. Sounds are emitted and amplified in the head through an oil filled cavity called a melon.

  10. Incoming vibrations are focused through the jaw and melon to the inner ear and the brain. The sounds are extremely accurate and VERY loud - can be used to stun prey. A single, short term noise of 150 dB may cause a human ear drum to rupture. A Blue whale can make a sound at 188 decibels. When whales enter the thermocline, sounds can be heard 1/4 of the distance around the earth.

  11. Diving: Lungs are completely filled and emptied quickly through the blow hole on top of the head. A trachea under the blow hole connects directly to lungs. They can not breathe through their mouth and can drown unless the top of the head is exposed to air. The nasal passage closes when relaxed to prevent water from entering the lungs, and allows them to sleep for short periods without drowning . Whales can sleep.

  12. Some whales go to depths of 13,000 ft. and only breathe every 90 minutes - smaller species have less range. NOAA Oxygen is stored in the muscles. Ribs are collapsible to reduce internal air pockets.

  13. Excretory: Specialized kidneys allow whales to drink salt water. The urine is very saline. Reproduction: Mating usually occurs in early summer. Implantation of the egg may be delayed several months, so that gestation finishes up in the warm summer months. Many whales only have one calf every 2-3 years. Babies weigh from 200 pounds to 1 ton. NOAA

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