LESSON 2 - SeaTrek Programs

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Lesson 1 www.seatrek.org V08/50531 Discovering Dolphins Bottlenose dolphins are marine mammals, meaning they exhibit all the characteristics of a mammal (give birth to live young, nurse their young, breathe air, have hair, and are warm-blooded), but live in an aquatic environment. Bottlenose dolphins belong to the order Cetacea, suborder Odontoceti (meaning toothed whales), and family Delphinidae. The scientific name for the Bottlenose dolphin is Tursiops truncatus. Dolphins are extremely well adapted to their aquatic environment. They have very streamlined bodies, anatomical features that aid in buoyancy, they are powerful swimmers and can withstand deep dives, they even have the ability to thermoregulate, and they live in social groups and habitats that are beneficial to them. Dolphins have very streamlined bodies to help them move efficiently through the water. Their streamlined adaptations include, telescoping (minimizing) skull shape and the nostrils of the animal are located at the top of the head, or dorsally, to form a blowhole. The animal uses it’s blowhole to breathe air as it surfaces in the water. This allows the animal to continue swimming without raising its entire head out of the water to breathe. A dolphin will generally breathe 2-3 times per minute. Also aiding in the dolphin’s sleek shape is the sloughing and shedding of skin every few hours. This helps to reduce drag for these animals while swimming. The skin cells that are shed are being replaced constantly. The absence of hair on the body also helps to reduce drag. Bottlenose dolphins are actually born with a few short hairs on both sides of the rostrum, which fall out very shortly after birth. Bottlenose dolphins are equipped will 3 sets of fins and flippers, all of which aid in the animal’s stability and mobility of the in water. The first set of flippers, the pectoral flippers, are located anteriorly on both sides of the body and are used for steering, stopping, and to aid in communication with conspecifics (other animals of the same species). The pectoral flippers are the only set of fins that contain bone, which looks similar to the bones in a human’s hand. The dorsal fin, located on the back of the animal’s body, is used for stability in the water, acting like the keel of a boat to balance the animal while swimming. The tail flukes are located at the posterior end of the animal and are used for propulsion. While swimming, the dolphin moves its tail flukes up and down, which provides lift and thrust. Muscles running the entire length of the vertebrae aid in dolphin’s powerful swimming and agility. Bottlenose dolphins usually swim at speeds of 5-10 kph (3-7 mph). These animals can reach speeds of 29-35 kph (18-22 mph) during “burst” swimming. A dolphin’s tail flukes and dorsal fin are made of a very strong, dense material called fibrous connective tissue. 4
Lesson 1 Discovering Dolphins To aid their buoyancy in the ocean, Bottlenose dolphins have light bones that are filled with oil, and a thick layer of blubber, or fat. This layer of blubber helps to keep the animal’s body temperature regulated at approximately 36.9º C (98.4ºF). Since dolphins are mammals, their bodies need to regulate a constant body temperature. The blubber layer accounts for approximately 18%-20% of the total body weight of the animal, and enhances the sleekness and streamlined form of the body. The blubber layer also acts as a fat reserve or storage. If the animal cannot find sufficient food, it may absorb some of the needed nutrition from this layer of fat. In order to thermoregulate their bodies, dolphins also have modified circulation. The circulatory system of these animals can adjust to conserve or diffuse body heat, so that the animal can maintain a constant body temperature using counter-current heat exchange. Counter-current heat exchange occurs in the flukes, dorsal fin, and flippers of the animal where large arteries, which carry oxygen-rich blood, are surrounded by veins, which absorb this oxygen-rich blood. The flukes, dorsal fin, and flippers do not have a blubber layer, making these areas the primary source for heat loss to the environment when the animal needs to lower it’s body temperature. When a dolphin dives, the blood Figure 1.1: Counter-current heat exchange flow concentrates to the core or center of the body and away from the surface of the body. This will help to maintain a constant body temperature by decreasing circulation throughout the body during deep dives. Generally, bottlenose dolphins do not need to dive to great depths to find sufficient food. Depending on the habitat, these animals tend to dive to depths of 3.0 – 45.7 m (10 – 150 ft.). However, they are capable of deep, prolonged dives, if necessary up to 500 m or 1,640 ft.. During prolonged dives, a dolphin’s body functions will adapt to conserve oxygen and energy. The heartbeat will generally decrease from 100 beats per minute to 12 beats per minute. Bottlenose dolphins’ lungs are small, reducing the organs’ energy requirements, making these animals efficient for deep dives. During a deep dive, the alveoli (sac in the lungs where oxygen and carbon dioxide are exchanged) will collapse due to the pressure, and in turn, prevent gas exchange. The lungs are reinforced with muscle and cartilage that remains open under pressure during these dives. In addition, the blood is shunted away from the appendages (fins and flippers) and is moved to the organs that critically need oxygen, such as the brain, heart, and lungs. Bottlenose dolphins’ muscles are very rich in myoglobin, an oxygen-binding protein, which helps prevent oxygen deficiency in muscles by storing oxygen. www.seatrek.org V08/50531 5
Page 1 and 2: Unit Overview The following materia
Page 3: Websites Developer Websites Mote Ma
Page 7 and 8: Activity 1.1: Cetacean Interrogatio
Page 9 and 10: Instructor Copy 9. Dolphins drink t
Page 11 and 12: Instructor Copy 22. Research in zoo
Page 13 and 14: Activity 1.2: Lights! Camera! Actio
Page 15 and 16: Lesson 2 Behind the Bottlenose The
Page 17 and 18: Lesson 2 Behind the Bottlenose To i
Page 19 and 20: Lesson 2: Behind the Bottlenose Act
Page 21 and 22: Activity 2.1 Dolphin Details Handou
Page 27 and 28: Activity 2.2: Sensational Sound! Gr
Page 29 and 30: Activity 2.2 Sensational Sound! Han
Page 31 and 32: Lesson 3 The Reel World Bottlenose
Page 33 and 34: Activity 3.1: Emotions in Motion Gr
Page 35 and 36: What are the different sounds used
Page 37 and 38: How else do dolphins communicate? D
Page 39 and 40: Social Behaviors Dolphins use a var
Page 41 and 42: Activity 3.1 Emotions in Motion Han
Page 43 and 44: Lesson 4 Research Reality SeaTrek
Page 45 and 46: Activity 4.1: Exhilarating Ethology
Page 47 and 48: Activity 4.1 Exhilarating Ethology
Page 49 and 50: Activity 4.2: SeaTrek Videoconferen
Page 51 and 52: 10. The videoconference made me mor
Page 53 and 54: Lesson 5 Fin Factor Sarasota Dolphi
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Activity 5.1 Bay Watch Instructor C
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Activity 5.1 Bay Watch Handout 5.1.
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Activity 5.2 Sarasota Bay Ecosystem
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Lesson 6 Conservation Captured As a
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Activity 6.1: Investigation Intenti
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Activity 6.1 Investigations Intenti
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Appendix A: Vocabulary Delphinidae
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Appendix A: Vocabulary Pollution Un
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Appendix B: National Standards (9-1
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Appendix C: Sunshine State Standard
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LESSON 2 - SeaTrek Programs

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